angular-cn/packages/core/schematics/migrations/static-queries/index.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 {Rule, SchematicsException, Tree} from '@angular-devkit/schematics';
import {dirname, relative} from 'path';
import * as ts from 'typescript';
import {getProjectTsConfigPaths} from '../../utils/project_tsconfig_paths';
import {analyzeNgQueryUsage} from './angular/analyze_query_usage';
import {NgQueryResolveVisitor} from './angular/ng_query_visitor';
import {getTransformedQueryCallExpr} from './transform';
import {parseTsconfigFile} from './typescript/tsconfig';
/** Entry point for the V8 static-query migration. */
export default function(): Rule {
return (tree: Tree) => {
const projectTsConfigPaths = getProjectTsConfigPaths(tree);
const basePath = process.cwd();
if (!projectTsConfigPaths.length) {
throw new SchematicsException(
'Could not find any tsconfig file. Cannot migrate queries ' +
'to explicit timing.');
}
for (const tsconfigPath of projectTsConfigPaths) {
runStaticQueryMigration(tree, tsconfigPath, basePath);
}
};
}
/**
* Runs the static query migration for the given TypeScript project. The schematic
* analyzes all queries within the project and sets up the query timing based on
* the current usage of the query property. e.g. a view query that is not used in any
* lifecycle hook does not need to be static and can be set up with "static: false".
*/
function runStaticQueryMigration(tree: Tree, tsconfigPath: string, basePath: string) {
const parsed = parseTsconfigFile(tsconfigPath, dirname(tsconfigPath));
const host = ts.createCompilerHost(parsed.options, true);
// We need to overwrite the host "readFile" method, as we want the TypeScript
// program to be based on the file contents in the virtual file tree. Otherwise
// if we run the migration for multiple tsconfig files which have intersecting
// source files, it can end up updating query definitions multiple times.
host.readFile = fileName => {
const buffer = tree.read(relative(basePath, fileName));
return buffer ? buffer.toString() : undefined;
};
const program = ts.createProgram(parsed.fileNames, parsed.options, host);
const typeChecker = program.getTypeChecker();
const queryVisitor = new NgQueryResolveVisitor(typeChecker);
const rootSourceFiles = program.getRootFileNames().map(f => program.getSourceFile(f) !);
const printer = ts.createPrinter();
// Analyze source files by detecting queries and class relations.
rootSourceFiles.forEach(sourceFile => queryVisitor.visitNode(sourceFile));
const {resolvedQueries, classMetadata} = queryVisitor;
// Walk through all source files that contain resolved queries and update
// the source files if needed. Note that we need to update multiple queries
// within a source file within the same recorder in order to not throw off
// the TypeScript node offsets.
resolvedQueries.forEach((queries, sourceFile) => {
const update = tree.beginUpdate(relative(basePath, sourceFile.fileName));
// 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 = analyzeNgQueryUsage(q, classMetadata, typeChecker);
const transformedNode = getTransformedQueryCallExpr(q, timing);
if (!transformedNode) {
return;
}
const newText = printer.printNode(ts.EmitHint.Unspecified, transformedNode, sourceFile);
// Replace the existing query decorator call expression with the updated
// call expression node.
update.remove(queryExpr.getStart(), queryExpr.getWidth());
update.insertRight(queryExpr.getStart(), newText);
});
tree.commitUpdate(update);
});
}