9ed4e3df60
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
68 lines
2.0 KiB
TypeScript
68 lines
2.0 KiB
TypeScript
/**
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* @license
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* Copyright Google Inc. All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import * as e from '../../../src/expression_parser/ast';
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import * as a from '../../../src/render3/r3_ast';
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export function findExpression(tmpl: a.Node[], expr: string): e.AST|null {
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const res = tmpl.reduce((found, node) => {
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if (found !== null) {
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return found;
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} else {
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return findExpressionInNode(node, expr);
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}
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}, null as e.AST | null);
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if (res instanceof e.ASTWithSource) {
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return res.ast;
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}
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return res;
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}
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function findExpressionInNode(node: a.Node, expr: string): e.AST|null {
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if (node instanceof a.Element || node instanceof a.Template) {
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return findExpression(
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[
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...node.inputs,
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...node.outputs,
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...node.children,
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],
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expr);
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} else if (node instanceof a.BoundAttribute || node instanceof a.BoundText) {
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const ts = toStringExpression(node.value);
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return toStringExpression(node.value) === expr ? node.value : null;
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} else if (node instanceof a.BoundEvent) {
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return toStringExpression(node.handler) === expr ? node.handler : null;
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} else {
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return null;
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}
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}
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export function toStringExpression(expr: e.AST): string {
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while (expr instanceof e.ASTWithSource) {
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expr = expr.ast;
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}
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if (expr instanceof e.PropertyRead) {
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if (expr.receiver instanceof e.ImplicitReceiver) {
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return expr.name;
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} else {
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return `${toStringExpression(expr.receiver)}.${expr.name}`;
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}
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} else if (expr instanceof e.ImplicitReceiver) {
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return '';
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} else if (expr instanceof e.Interpolation) {
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let str = '{{';
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for (let i = 0; i < expr.expressions.length; i++) {
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str += expr.strings[i] + toStringExpression(expr.expressions[i]);
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}
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str += expr.strings[expr.strings.length - 1] + '}}';
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return str;
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} else {
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throw new Error(`Unsupported type: ${(expr as any).constructor.name}`);
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}
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}
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