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feat(ivy): introduce a new compiler API for operating on templates (#26203) 

This commit introduces the "t2" API, which processes parsed template ASTs
and performs a number of functions such as binding (the process of
semantically interpreting cross-references within the template) and
directive matching. The API is modeled on TypeScript's TypeChecker API,
with oracle methods that give access to collected metadata.

This work is a prerequisite for the upcoming template type-checking
functionality, and will also become the basis for a refactored
TemplateDefinitionBuilder.

PR Close #26203
This commit is contained in:
Alex Rickabaugh 2018-09-21 15:42:07 -07:00 committed by Jason Aden
parent a2da485d90
commit 9ed4e3df60
5 changed files with 798 additions and 0 deletions
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3
packages/compiler/src/compiler.ts
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@ -81,6 +81,9 @@ export {getParseErrors, isSyntaxError, syntaxError, Version} from './util';
export {SourceMap} from './output/source_map'; export {SourceMap} from './output/source_map';
export * from './injectable_compiler_2'; export * from './injectable_compiler_2';
export * from './render3/view/api'; export * from './render3/view/api';
export {BoundAttribute as TmplAstBoundAttribute, BoundEvent as TmplAstBoundEvent, BoundText as TmplAstBoundText, Content as TmplAstContent, Element as TmplAstElement, Node as TmplAstNode, Reference as TmplAstReference, Template as TmplAstTemplate, Text as TmplAstText, TextAttribute as TmplAstTextAttribute, Variable as TmplAstVariable,} from './render3/r3_ast';
export * from './render3/view/t2_api';
export * from './render3/view/t2_binder';
export {jitExpression} from './render3/r3_jit'; export {jitExpression} from './render3/r3_jit';
export {R3DependencyMetadata, R3FactoryMetadata, R3ResolvedDependencyType} from './render3/r3_factory'; export {R3DependencyMetadata, R3FactoryMetadata, R3ResolvedDependencyType} from './render3/r3_factory';
export {compileInjector, compileNgModule, R3InjectorMetadata, R3NgModuleMetadata} from './render3/r3_module_compiler'; export {compileInjector, compileNgModule, R3InjectorMetadata, R3NgModuleMetadata} from './render3/r3_module_compiler';

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packages/compiler/src/render3/view/t2_api.ts Normal file
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@ -0,0 +1,139 @@
/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {AST} from '../../expression_parser/ast';
import {BoundAttribute, BoundEvent, Element, Node, Reference, Template, TextAttribute, Variable} from '../r3_ast';
/*
* t2 is the replacement for the `TemplateDefinitionBuilder`. It handles the operations of
* analyzing Angular templates, extracting semantic info, and ultimately producing a template
* definition function which renders the template using Ivy instructions.
*
* t2 data is also utilized by the template type-checking facilities to understand a template enough
* to generate type-checking code for it.
*/
/**
* A logical target for analysis, which could contain a template or other types of bindings.
*/
export interface Target { template?: Node[]; }
/**
* Metadata regarding a directive that's needed to match it against template elements. This is
* provided by a consumer of the t2 APIs.
*/
export interface DirectiveMeta {
/**
* Name of the directive class (used for debugging).
*/
name: string;
/**
* Whether the directive is a component.
*/
isComponent: boolean;
/**
* Set of inputs which this directive claims.
*
* Goes from property names to field names.
*/
inputs: {[property: string]: string};
/**
* Set of outputs which this directive claims.
*
* Goes from property names to field names.
*/
outputs: {[property: string]: string};
/**
* Name under which the directive is exported, if any (exportAs in Angular).
*
* Null otherwise
*/
exportAs: string|null;
}
/**
* Interface to the binding API, which processes a template and returns an object similar to the
* `ts.TypeChecker`.
*
* The returned `BoundTarget` has an API for extracting information about the processed target.
*/
export interface TargetBinder<D extends DirectiveMeta> { bind(target: Target): BoundTarget<D>; }
/**
* Result of performing the binding operation against a `Target`.
*
* The original `Target` is accessible, as well as a suite of methods for extracting binding
* information regarding the `Target`.
*
* @param DirectiveT directive metadata type
*/
export interface BoundTarget<DirectiveT extends DirectiveMeta> {
/**
* Get the original `Target` that was bound.
*/
readonly target: Target;
/**
* For a given template node (either an `Element` or a `Template`), get the set of directives
* which matched the node, if any.
*/
getDirectivesOfNode(node: Element|Template): DirectiveT[]|null;
/**
* For a given `Reference`, get the reference's target - either an `Element`, a `Template`, or
* a directive on a particular node.
*/
getReferenceTarget(ref: Reference): {directive: DirectiveT, node: Element|Template}|Element
|Template|null;
/**
* For a given binding, get the entity to which the binding is being made.
*
* This will either be a directive or the node itself.
*/
getConsumerOfBinding(binding: BoundAttribute|BoundEvent|TextAttribute): DirectiveT|Element
|Template|null;
/**
* If the given `AST` expression refers to a `Reference` or `Variable` within the `Target`, then
* return that.
*
* Otherwise, returns `null`.
*
* This is only defined for `AST` expressions that read or write to a property of an
* `ImplicitReceiver`.
*/
getExpressionTarget(expr: AST): Reference|Variable|null;
/**
* Given a particular `Reference` or `Variable`, get the `Template` which created it.
*
* All `Variable`s are defined on templates, so this will always return a value for a `Variable`
* from the `Target`. For `Reference`s this only returns a value if the `Reference` points to a
* `Template`. Returns `null` otherwise.
*/
getTemplateOfSymbol(symbol: Reference|Variable): Template|null;
/**
* Get the nesting level of a particular `Template`.
*
* This starts at 1 for top-level `Template`s within the `Target` and increases for `Template`s
* nested at deeper levels.
*/
getNestingLevel(template: Template): number;
/**
* Get a list of all the directives used by the target.
*/
getUsedDirectives(): DirectiveT[];
}

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packages/compiler/src/render3/view/t2_binder.ts Normal file
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@ -0,0 +1,528 @@
/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {AST, ImplicitReceiver, MethodCall, PropertyRead, PropertyWrite, RecursiveAstVisitor, SafeMethodCall, SafePropertyRead} from '../../expression_parser/ast';
import {CssSelector, SelectorMatcher} from '../../selector';
import {BoundAttribute, BoundEvent, BoundText, Content, Element, Node, Reference, Template, Text, TextAttribute, Variable, Visitor} from '../r3_ast';
import {BoundTarget, DirectiveMeta, Target, TargetBinder} from './t2_api';
import {getAttrsForDirectiveMatching} from './util';
/**
* Processes `Target`s with a given set of directives and performs a binding operation, which
* returns an object similar to TypeScript's `ts.TypeChecker` that contains knowledge about the
* target.
*/
export class R3TargetBinder<DirectiveT extends DirectiveMeta> implements TargetBinder<DirectiveT> {
constructor(private directiveMatcher: SelectorMatcher<DirectiveT>) {}
/**
* Perform a binding operation on the given `Target` and return a `BoundTarget` which contains
* metadata about the types referenced in the template.
*/
bind(target: Target): BoundTarget<DirectiveT> {
if (!target.template) {
// TODO(alxhub): handle targets which contain things like HostBindings, etc.
throw new Error('Binding without a template not yet supported');
}
// First, parse the template into a `Scope` structure. This operation captures the syntactic
// scopes in the template and makes them available for later use.
const scope = Scope.apply(target.template);
// Next, perform directive matching on the template using the `DirectiveBinder`. This returns:
// - directives: Map of nodes (elements & ng-templates) to the directives on them.
// - bindings: Map of inputs, outputs, and attributes to the directive/element that claims
// them. TODO(alxhub): handle multiple directives claiming an input/output/etc.
// - references: Map of #references to their targets.
const {directives, bindings, references} =
DirectiveBinder.apply(target.template, this.directiveMatcher);
// Finally, run the TemplateBinder to bind references, variables, and other entities within the
// template. This extracts all the metadata that doesn't depend on directive matching.
const {expressions, symbols, nestingLevel} = TemplateBinder.apply(target.template, scope);
return new R3BoundTarget(
target, directives, bindings, references, expressions, symbols, nestingLevel);
}
}
/**
* Represents a binding scope within a template.
*
* Any variables, references, or other named entities declared within the template will
* be captured and available by name in `namedEntities`. Additionally, child templates will
* be analyzed and have their child `Scope`s available in `childScopes`.
*/
class Scope implements Visitor {
/**
* Named members of the `Scope`, such as `Reference`s or `Variable`s.
*/
readonly namedEntities = new Map<string, Reference|Variable>();
/**
* Child `Scope`s for immediately nested `Template`s.
*/
readonly childScopes = new Map<Template, Scope>();
private constructor(readonly parentScope?: Scope) {}
/**
* Process a template (either as a `Template` sub-template with variables, or a plain array of
* template `Node`s) and construct its `Scope`.
*/
static apply(template: Template|Node[]): Scope {
const scope = new Scope();
scope.ingest(template);
return scope;
}
/**
* Internal method to process the template and populate the `Scope`.
*/
private ingest(template: Template|Node[]): void {
if (template instanceof Template) {
// Variables on an <ng-template> are defined in the inner scope.
template.variables.forEach(node => this.visitVariable(node));
// Process the nodes of the template.
template.children.forEach(node => node.visit(this));
} else {
// No overarching `Template` instance, so process the nodes directly.
template.forEach(node => node.visit(this));
}
}
visitElement(element: Element) {
// `Element`s in the template may have `Reference`s which are captured in the scope.
element.references.forEach(node => this.visitReference(node));
// Recurse into the `Element`'s children.
element.children.forEach(node => node.visit(this));
}
visitTemplate(template: Template) {
// References on a <ng-template> are defined in the outer scope, so capture them before
// processing the template's child scope.
template.references.forEach(node => this.visitReference(node));
// Next, create an inner scope and process the template within it.
const scope = new Scope(this);
scope.ingest(template);
this.childScopes.set(template, scope);
}
visitVariable(variable: Variable) {
// Declare the variable if it's not already.
this.maybeDeclare(variable);
}
visitReference(reference: Reference) {
// Declare the variable if it's not already.
this.maybeDeclare(reference);
}
// Unused visitors.
visitContent(content: Content) {}
visitBoundAttribute(attr: BoundAttribute) {}
visitBoundEvent(event: BoundEvent) {}
visitBoundText(text: BoundText) {}
visitText(text: Text) {}
visitTextAttribute(attr: TextAttribute) {}
private maybeDeclare(thing: Reference|Variable) {
// Declare something with a name, as long as that name isn't taken.
if (!this.namedEntities.has(thing.name)) {
this.namedEntities.set(thing.name, thing);
}
}
/**
* Look up a variable within this `Scope`.
*
* This can recurse into a parent `Scope` if it's available.
*/
lookup(name: string): Reference|Variable|null {
if (this.namedEntities.has(name)) {
// Found in the local scope.
return this.namedEntities.get(name) !;
} else if (this.parentScope !== undefined) {
// Not in the local scope, but there's a parent scope so check there.
return this.parentScope.lookup(name);
} else {
// At the top level and it wasn't found.
return null;
}
}
/**
* Get the child scope for a `Template`.
*
* This should always be defined.
*/
getChildScope(template: Template): Scope {
const res = this.childScopes.get(template);
if (res === undefined) {
throw new Error(`Assertion error: child scope for ${template} not found`);
}
return res;
}
}
/**
* Processes a template and matches directives on nodes (elements and templates).
*
* Usually used via the static `apply()` method.
*/
class DirectiveBinder<DirectiveT extends DirectiveMeta> implements Visitor {
constructor(
private matcher: SelectorMatcher<DirectiveT>,
private directives: Map<Element|Template, DirectiveT[]>,
private bindings: Map<BoundAttribute|BoundEvent|TextAttribute, DirectiveT|Element|Template>,
private references:
Map<Reference, {directive: DirectiveT, node: Element|Template}|Element|Template>) {}
/**
* Process a template (list of `Node`s) and perform directive matching against each node.
*
* @param template the list of template `Node`s to match (recursively).
* @param selectorMatcher a `SelectorMatcher` containing the directives that are in scope for
* this template.
* @returns three maps which contain information about directives in the template: the
* `directives` map which lists directives matched on each node, the `bindings` map which
* indicates which directives claimed which bindings (inputs, outputs, etc), and the `references`
* map which resolves #references (`Reference`s) within the template to the named directive or
* template node.
*/
static apply<DirectiveT extends DirectiveMeta>(
template: Node[], selectorMatcher: SelectorMatcher<DirectiveT>): {
directives: Map<Element|Template, DirectiveT[]>,
bindings: Map<BoundAttribute|BoundEvent|TextAttribute, DirectiveT|Element|Template>,
references: Map<Reference, {directive: DirectiveT, node: Element|Template}|Element|Template>,
} {
const directives = new Map<Element|Template, DirectiveT[]>();
const bindings =
new Map<BoundAttribute|BoundEvent|TextAttribute, DirectiveT|Element|Template>();
const references =
new Map<Reference, {directive: DirectiveT, node: Element | Template}|Element|Template>();
const matcher = new DirectiveBinder(selectorMatcher, directives, bindings, references);
matcher.ingest(template);
return {directives, bindings, references};
}
private ingest(template: Node[]): void { template.forEach(node => node.visit(this)); }
visitElement(element: Element): void { this.visitElementOrTemplate(element.name, element); }
visitTemplate(template: Template): void { this.visitElementOrTemplate('ng-template', template); }
visitElementOrTemplate(tag: string, node: Element|Template): void {
// First, determine the HTML shape of the node for the purpose of directive matching.
// Do this by building up a `CssSelector` for the node.
const cssSelector = new CssSelector();
cssSelector.setElement(tag);
// Add attributes to the CSS selector.
const attrs = getAttrsForDirectiveMatching(node);
Object.getOwnPropertyNames(attrs).forEach((name) => {
const value = attrs[name];
cssSelector.addAttribute(name, value);
// Treat the 'class' attribute specially.
if (name.toLowerCase() === 'class') {
const classes = value.trim().split(/\s+/g);
classes.forEach(className => cssSelector.addClassName(className));
}
});
// Next, use the `SelectorMatcher` to get the list of directives on the node.
const directives: DirectiveT[] = [];
this.matcher.match(cssSelector, (_, directive) => directives.push(directive));
if (directives.length > 0) {
this.directives.set(node, directives);
}
// Resolve any references that are created on this node.
node.references.forEach(ref => {
let dirTarget: DirectiveT|null = null;
// If the reference expression is empty, then it matches the "primary" directive on the node
// (if there is one). Otherwise it matches the host node itself (either an element or
// <ng-template> node).
if (ref.value.trim() === '') {
// This could be a reference to a component if there is one.
dirTarget = directives.find(dir => dir.isComponent) || null;
} else {
// This is a reference to a directive exported via exportAs. One should exist.
dirTarget = directives.find(dir => dir.exportAs === ref.value) || null;
// Check if a matching directive was found, and error if it wasn't.
if (dirTarget === null) {
// TODO(alxhub): Return an error value here that can be used for template validation.
throw new Error(`Assertion error: failed to find directive with exportAs: ${ref.value}`);
}
}
if (dirTarget !== null) {
// This reference points to a directive.
this.references.set(ref, {directive: dirTarget, node});
} else {
// This reference points to the node itself.
this.references.set(ref, node);
}
});
// Associate bindings on the node with directives or with the node itself.
// Inputs:
[...node.attributes, ...node.inputs].forEach(binding => {
let dir = directives.find(dir => dir.inputs.hasOwnProperty(binding.name));
if (dir !== undefined) {
this.bindings.set(binding, dir);
} else {
this.bindings.set(binding, node);
}
});
// Outputs:
node.outputs.forEach(binding => {
let dir = directives.find(dir => dir.outputs.hasOwnProperty(binding.name));
if (dir !== undefined) {
this.bindings.set(binding, dir);
} else {
this.bindings.set(binding, node);
}
});
// Recurse into the node's children.
node.children.forEach(child => child.visit(this));
}
// Unused visitors.
visitContent(content: Content): void {}
visitVariable(variable: Variable): void {}
visitReference(reference: Reference): void {}
visitTextAttribute(attribute: TextAttribute): void {}
visitBoundAttribute(attribute: BoundAttribute): void {}
visitBoundEvent(attribute: BoundEvent): void {}
visitBoundAttributeOrEvent(node: BoundAttribute|BoundEvent) {}
visitText(text: Text): void {}
visitBoundText(text: BoundText): void {}
}
/**
* Processes a template and extract metadata about expressions and symbols within.
*
* This is a companion to the `DirectiveBinder` that doesn't require knowledge of directives matched
* within the template in order to operate.
*
* Expressions are visited by the superclass `RecursiveAstVisitor`, with custom logic provided
* by overridden methods from that visitor.
*/
class TemplateBinder extends RecursiveAstVisitor implements Visitor {
private visitNode: (node: Node) => void;
private constructor(
private bindings: Map<AST, Reference|Variable>,
private symbols: Map<Reference|Variable, Template>,
private nestingLevel: Map<Template, number>, private scope: Scope,
private template: Template|null, private level: number) {
super();
// Save a bit of processing time by constructing this closure in advance.
this.visitNode = (node: Node) => node.visit(this);
}
/**
* Process a template and extract metadata about expressions and symbols within.
*
* @param template the nodes of the template to process
* @param scope the `Scope` of the template being processed.
* @returns three maps which contain metadata about the template: `expressions` which interprets
* special `AST` nodes in expressions as pointing to references or variables declared within the
* template, `symbols` which maps those variables and references to the nested `Template` which
* declares them, if any, and `nestingLevel` which associates each `Template` with a integer
* nesting level (how many levels deep within the template structure the `Template` is), starting
* at 1.
*/
static apply(template: Node[], scope: Scope): {
expressions: Map<AST, Reference|Variable>,
symbols: Map<Variable|Reference, Template>,
nestingLevel: Map<Template, number>,
} {
const expressions = new Map<AST, Reference|Variable>();
const symbols = new Map<Variable|Reference, Template>();
const nestingLevel = new Map<Template, number>();
// The top-level template has nesting level 0.
const binder = new TemplateBinder(
expressions, symbols, nestingLevel, scope, template instanceof Template ? template : null,
0);
binder.ingest(template);
return {expressions, symbols, nestingLevel};
}
private ingest(template: Template|Node[]): void {
if (template instanceof Template) {
// For <ng-template>s, process inputs, outputs, variables, and child nodes. References were
// processed in the scope of the containing template.
template.inputs.forEach(this.visitNode);
template.outputs.forEach(this.visitNode);
template.variables.forEach(this.visitNode);
template.children.forEach(this.visitNode);
// Set the nesting level.
this.nestingLevel.set(template, this.level);
} else {
// Visit each node from the top-level template.
template.forEach(this.visitNode);
}
}
visitElement(element: Element) {
// Vist the inputs, outputs, and children of the element.
element.inputs.forEach(this.visitNode);
element.outputs.forEach(this.visitNode);
element.children.forEach(this.visitNode);
}
visitTemplate(template: Template) {
// First, visit the inputs, outputs of the template node.
template.inputs.forEach(this.visitNode);
template.outputs.forEach(this.visitNode);
// References are also evaluated in the outer context.
template.references.forEach(this.visitNode);
// Next, recurse into the template using its scope, and bumping the nesting level up by one.
const childScope = this.scope.getChildScope(template);
const binder = new TemplateBinder(
this.bindings, this.symbols, this.nestingLevel, childScope, template, this.level + 1);
binder.ingest(template);
}
visitVariable(variable: Variable) {
// Register the `Variable` as a symbol in the current `Template`.
if (this.template !== null) {
this.symbols.set(variable, this.template);
}
}
visitReference(reference: Reference) {
// Register the `Reference` as a symbol in the current `Template`.
if (this.template !== null) {
this.symbols.set(reference, this.template);
}
}
// Unused template visitors
visitText(text: Text) {}
visitContent(content: Content) {}
visitTextAttribute(attribute: TextAttribute) {}
// The remaining visitors are concerned with processing AST expressions within template bindings
visitBoundAttribute(attribute: BoundAttribute) { attribute.value.visit(this); }
visitBoundEvent(event: BoundEvent) { event.handler.visit(this); }
visitBoundText(text: BoundText) { text.value.visit(this); }
// These five types of AST expressions can refer to expression roots, which could be variables
// or references in the current scope.
visitPropertyRead(ast: PropertyRead, context: any): any {
this.maybeMap(context, ast, ast.name);
return super.visitPropertyRead(ast, context);
}
visitSafePropertyRead(ast: SafePropertyRead, context: any): any {
this.maybeMap(context, ast, ast.name);
return super.visitSafePropertyRead(ast, context);
}
visitPropertyWrite(ast: PropertyWrite, context: any): any {
this.maybeMap(context, ast, ast.name);
return super.visitPropertyWrite(ast, context);
}
visitMethodCall(ast: MethodCall, context: any): any {
this.maybeMap(context, ast, ast.name);
return super.visitMethodCall(ast, context);
}
visitSafeMethodCall(ast: SafeMethodCall, context: any): any {
this.maybeMap(context, ast, ast.name);
return super.visitSafeMethodCall(ast, context);
}
private maybeMap(
scope: Scope, ast: PropertyRead|SafePropertyRead|PropertyWrite|MethodCall|SafeMethodCall,
name: string): void {
// If the receiver of the expression isn't the `ImplicitReceiver`, this isn't the root of an
// `AST` expression that maps to a `Variable` or `Reference`.
if (!(ast.receiver instanceof ImplicitReceiver)) {
return;
}
// Check whether the name exists in the current scope. If so, map it. Otherwise, the name is
// probably a property on the top-level component context.
let target = this.scope.lookup(name);
if (target !== null) {
this.bindings.set(ast, target);
}
}
}
/**
* Metadata container for a `Target` that allows queries for specific bits of metadata.
*
* See `BoundTarget` for documentation on the individual methods.
*/
export class R3BoundTarget<DirectiveT extends DirectiveMeta> implements BoundTarget<DirectiveT> {
constructor(
readonly target: Target, private directives: Map<Element|Template, DirectiveT[]>,
private bindings: Map<BoundAttribute|BoundEvent|TextAttribute, DirectiveT|Element|Template>,
private references:
Map<BoundAttribute|BoundEvent|Reference|TextAttribute,
{directive: DirectiveT, node: Element|Template}|Element|Template>,
private exprTargets: Map<AST, Reference|Variable>,
private symbols: Map<Reference|Variable, Template>,
private nestingLevel: Map<Template, number>) {}
getDirectivesOfNode(node: Element|Template): DirectiveT[]|null {
return this.directives.get(node) || null;
}
getReferenceTarget(ref: Reference): {directive: DirectiveT, node: Element|Template}|Element
|Template|null {
return this.references.get(ref) || null;
}
getConsumerOfBinding(binding: BoundAttribute|BoundEvent|TextAttribute): DirectiveT|Element
|Template|null {
return this.bindings.get(binding) || null;
}
getExpressionTarget(expr: AST): Reference|Variable|null {
return this.exprTargets.get(expr) || null;
}
getTemplateOfSymbol(symbol: Reference|Variable): Template|null {
return this.symbols.get(symbol) || null;
}
getNestingLevel(template: Template): number { return this.nestingLevel.get(template) || 0; }
getUsedDirectives(): DirectiveT[] {
const set = new Set<DirectiveT>();
this.directives.forEach(dirs => dirs.forEach(dir => set.add(dir)));
return Array.from(set.values());
}
}

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/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import * as e from '../../../src/expression_parser/ast';
import * as a from '../../../src/render3/r3_ast';
import {DirectiveMeta} from '../../../src/render3/view/t2_api';
import {R3TargetBinder} from '../../../src/render3/view/t2_binder';
import {parseTemplate} from '../../../src/render3/view/template';
import {CssSelector, SelectorMatcher} from '../../../src/selector';
import {findExpression} from './util';
function makeSelectorMatcher(): SelectorMatcher<DirectiveMeta> {
const matcher = new SelectorMatcher<DirectiveMeta>();
matcher.addSelectables(CssSelector.parse('[ngFor][ngForOf]'), {
name: 'NgFor',
exportAs: null,
inputs: {'ngForOf': 'ngForOf'},
outputs: {},
isComponent: false,
});
return matcher;
}
describe('t2 binding', () => {
it('should bind a simple template', () => {
const template =
parseTemplate('<div *ngFor="let item of items">{{item.name}}</div>', '', {}, '');
const binder = new R3TargetBinder(new SelectorMatcher<DirectiveMeta>());
const res = binder.bind({template: template.nodes});
const itemBinding = (findExpression(template.nodes, '{{item.name}}') !as e.Interpolation)
.expressions[0] as e.PropertyRead;
const item = itemBinding.receiver;
const itemTarget = res.getExpressionTarget(item);
if (!(itemTarget instanceof a.Variable)) {
return fail('Expected item to point to a Variable');
}
expect(itemTarget.value).toBe('$implicit');
const itemTemplate = res.getTemplateOfSymbol(itemTarget);
expect(itemTemplate).not.toBeNull();
expect(res.getNestingLevel(itemTemplate !)).toBe(1);
});
it('should match directives when binding a simple template', () => {
const template =
parseTemplate('<div *ngFor="let item of items">{{item.name}}</div>', '', {}, '');
const binder = new R3TargetBinder(makeSelectorMatcher());
const res = binder.bind({template: template.nodes});
const tmpl = template.nodes[0] as a.Template;
const directives = res.getDirectivesOfNode(tmpl) !;
expect(directives).not.toBeNull();
expect(directives.length).toBe(1);
expect(directives[0].name).toBe('NgFor');
});
});

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@ -0,0 +1,67 @@
/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import * as e from '../../../src/expression_parser/ast';
import * as a from '../../../src/render3/r3_ast';
export function findExpression(tmpl: a.Node[], expr: string): e.AST|null {
const res = tmpl.reduce((found, node) => {
if (found !== null) {
return found;
} else {
return findExpressionInNode(node, expr);
}
}, null as e.AST | null);
if (res instanceof e.ASTWithSource) {
return res.ast;
}
return res;
}
function findExpressionInNode(node: a.Node, expr: string): e.AST|null {
if (node instanceof a.Element || node instanceof a.Template) {
return findExpression(
[
...node.inputs,
...node.outputs,
...node.children,
],
expr);
} else if (node instanceof a.BoundAttribute || node instanceof a.BoundText) {
const ts = toStringExpression(node.value);
return toStringExpression(node.value) === expr ? node.value : null;
} else if (node instanceof a.BoundEvent) {
return toStringExpression(node.handler) === expr ? node.handler : null;
} else {
return null;
}
}
export function toStringExpression(expr: e.AST): string {
while (expr instanceof e.ASTWithSource) {
expr = expr.ast;
}
if (expr instanceof e.PropertyRead) {
if (expr.receiver instanceof e.ImplicitReceiver) {
return expr.name;
} else {
return `${toStringExpression(expr.receiver)}.${expr.name}`;
}
} else if (expr instanceof e.ImplicitReceiver) {
return '';
} else if (expr instanceof e.Interpolation) {
let str = '{{';
for (let i = 0; i < expr.expressions.length; i++) {
str += expr.strings[i] + toStringExpression(expr.expressions[i]);
}
str += expr.strings[expr.strings.length - 1] + '}}';
return str;
} else {
throw new Error(`Unsupported type: ${(expr as any).constructor.name}`);
}
}