angular-cn/packages/core/schematics/migrations/google3/explicitQueryTimingRule.ts

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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 {Replacement, RuleFailure, Rules} from 'tslint';
import * as ts from 'typescript';
import {NgComponentTemplateVisitor} from '../../utils/ng_component_template';
import {NgQueryResolveVisitor} from '../static-queries/angular/ng_query_visitor';
import {QueryTiming} from '../static-queries/angular/query-definition';
import {QueryUsageStrategy} from '../static-queries/strategies/usage_strategy/usage_strategy';
import {getTransformedQueryCallExpr} from '../static-queries/transform';
const FAILURE_MESSAGE = 'Query does not explicitly specify its timing. Read more here: ' +
'https://github.com/angular/angular/pull/28810';
/**
* Rule that reports if an Angular "ViewChild" or "ContentChild" query is not explicitly
* specifying its timing. The rule also provides TSLint automatic replacements that can
* be applied in order to automatically migrate to the explicit query timing API.
*/
export class Rule extends Rules.TypedRule {
applyWithProgram(sourceFile: ts.SourceFile, program: ts.Program): RuleFailure[] {
const typeChecker = program.getTypeChecker();
const queryVisitor = new NgQueryResolveVisitor(program.getTypeChecker());
const templateVisitor = new NgComponentTemplateVisitor(typeChecker);
const rootSourceFiles = program.getRootFileNames().map(f => program.getSourceFile(f) !);
const printer = ts.createPrinter();
const failures: RuleFailure[] = [];
// Analyze source files by detecting queries, class relations and component templates.
rootSourceFiles.forEach(sourceFile => {
queryVisitor.visitNode(sourceFile);
templateVisitor.visitNode(sourceFile);
});
const {resolvedQueries, classMetadata} = queryVisitor;
// Add all resolved templates to the class metadata so that we can also
// check component templates for static query usage.
templateVisitor.resolvedTemplates.forEach(template => {
if (classMetadata.has(template.container)) {
classMetadata.get(template.container) !.template = template;
}
});
const queries = resolvedQueries.get(sourceFile);
const usageStrategy = new QueryUsageStrategy(classMetadata, typeChecker);
// No queries detected for the given source file.
if (!queries) {
return [];
}
// Compute the query usage for all resolved queries and update the
// query definitions to explicitly declare the query timing (static or dynamic)
queries.forEach(q => {
const queryExpr = q.decorator.node.expression;
const {timing, message} = usageStrategy.detectTiming(q);
const result = getTransformedQueryCallExpr(q, timing, !!message);
if (!result) {
return;
}
const newText = printer.printNode(ts.EmitHint.Unspecified, result.node, sourceFile);
// Replace the existing query decorator call expression with the
// updated call expression node.
const fix = new Replacement(queryExpr.getStart(), queryExpr.getWidth(), newText);
const failureMessage = `${FAILURE_MESSAGE}. Based on analysis of the query it can be ` +
`marked as "{static: ${(timing === QueryTiming.STATIC).toString()}}".`;
failures.push(new RuleFailure(
sourceFile, queryExpr.getStart(), queryExpr.getEnd(), failureMessage, this.ruleName,
fix));
});
return failures;
}
}