Add support for marker functions, to be able to extract strings not directly passed to TranslateService. Closes #10

README.md

@@ -50,6 +50,18 @@ If you want to use spaces instead, you can do the following:
 
 `ngx-translate-extract -i ./src -o ./src/i18n/en.json --format-indentation '  '`
 
+## Mark strings for extraction using a marker function
+If, for some reason, you want to extract strings not passed directly to TranslateService, you can wrap them in a custom marker function.
+
+```ts
+import { _ } from '@biesbjerg/ngx-translate-extract';
+
+_('Extract me');
+```
+
+Add the `marker` argument when running the extract script:
+
+`ngx-translate-extract ... -m _`
 
 Modify the scripts arguments as required.
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@biesbjerg/ngx-translate-extract",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "description": "Extract strings from projects using ngx-translate",
   "main": "dist/index.js",
   "typings": "dist/index.d.ts",

src/cli/cli.ts

@@ -3,6 +3,7 @@ import { ParserInterface } from '../parsers/parser.interface';
 import { PipeParser } from '../parsers/pipe.parser';
 import { DirectiveParser } from '../parsers/directive.parser';
 import { ServiceParser } from '../parsers/service.parser';
+import { FunctionParser } from '../parsers/function.parser';
 import { CompilerInterface } from '../compilers/compiler.interface';
 import { CompilerFactory } from '../compilers/compiler.factory';
 
@@ -44,6 +45,12 @@ export const cli = yargs
 		normalize: true,
 		required: true
 	})
+	.option('marker', {
+		alias: 'm',
+		describe: 'Extract strings passed to a marker function',
+		default: false,
+		type: 'string'
+	})
 	.option('format', {
 		alias: 'f',
 		describe: 'Output format',
@@ -78,22 +85,28 @@ export const cli = yargs
 	.exitProcess(true)
 	.parse(process.argv);
 
-const parsers: ParserInterface[] = [
-	new ServiceParser(),
-	new PipeParser(),
-	new DirectiveParser()
-];
-
-const compiler: CompilerInterface = CompilerFactory.create(cli.format, {
-	indentation: cli.formatIndentation
-});
-
-new ExtractTask(cli.input, cli.output, {
+const extract = new ExtractTask(cli.input, cli.output, {
 	replace: cli.replace,
 	sort: cli.sort,
 	clean: cli.clean,
 	patterns: cli.patterns
-})
-.setParsers(parsers)
-.setCompiler(compiler)
-.execute();
+});
+
+const compiler: CompilerInterface = CompilerFactory.create(cli.format, {
+	indentation: cli.formatIndentation
+});
+extract.setCompiler(compiler);
+
+const parsers: ParserInterface[] = [
+	new PipeParser(),
+	new DirectiveParser(),
+	new ServiceParser()
+];
+if (cli.marker) {
+	parsers.push(new FunctionParser({
+		identifier: cli.marker
+	}));
+}
+extract.setParsers(parsers);
+
+extract.execute();

src/cli/tasks/extract.task.ts

@@ -41,11 +41,6 @@ export class ExtractTask implements TaskInterface {
 		}
 
 		const collection = this._extract();
-		if (collection.isEmpty()) {
-			this._out(chalk.yellow('Did not find any extractable strings\n'));
-			return;
-		}
-
 		this._out(chalk.green('Extracted %d strings\n'), collection.count());
 		this._save(collection);
 	}

src/index.ts

@@ -1,5 +1,5 @@
 export * from './utils/translation.collection';
-export * from './utils/ast-utils';
+export * from './utils/utils';
 
 export * from './cli/cli';
 export * from './cli/tasks/task.interface';
@@ -7,9 +7,11 @@ export * from './cli/tasks/extract.task';
 
 export * from './parsers/parser.interface';
 export * from './parsers/abstract-template.parser';
+export * from './parsers/abstract-ast.parser';
 export * from './parsers/directive.parser';
 export * from './parsers/pipe.parser';
 export * from './parsers/service.parser';
+export * from './parsers/function.parser';
 
 export * from './compilers/compiler.interface';
 export * from './compilers/compiler.factory';

src/parsers/abstract-ast.parser.ts

@@ -0,0 +1,69 @@
+import * as ts from 'typescript';
+
+export abstract class AbstractAstParser {
+
+	protected _sourceFile: ts.SourceFile;
+
+	protected _createSourceFile(path: string, contents: string): ts.SourceFile {
+		return ts.createSourceFile(path, contents, null, /*setParentNodes */ false);
+	}
+
+	/**
+	 * Get strings from function call's first argument
+	 */
+	protected _getCallArgStrings(callNode: ts.CallExpression): string[] {
+		if (!callNode.arguments.length) {
+			return;
+		}
+
+		const firstArg = callNode.arguments[0];
+		switch (firstArg.kind) {
+			case ts.SyntaxKind.StringLiteral:
+			case ts.SyntaxKind.FirstTemplateToken:
+				return [(firstArg as ts.StringLiteral).text];
+			case ts.SyntaxKind.ArrayLiteralExpression:
+				return (firstArg as ts.ArrayLiteralExpression).elements
+					.map((element: ts.StringLiteral) => element.text);
+			case ts.SyntaxKind.Identifier:
+				console.log('WARNING: We cannot extract variable values passed to TranslateService (yet)');
+				break;
+			default:
+				console.log(`SKIP: Unknown argument type: '${this._syntaxKindToName(firstArg.kind)}'`, firstArg);
+		}
+	}
+
+	/**
+	 * Find all child nodes of a kind
+	 */
+	protected _findNodes(node: ts.Node, kind: ts.SyntaxKind, onlyOne: boolean = false): ts.Node[] {
+		if (node.kind === kind && onlyOne) {
+			return [node];
+		}
+
+		const childrenNodes: ts.Node[] = node.getChildren(this._sourceFile);
+		const initialValue: ts.Node[] = node.kind === kind ? [node] : [];
+
+		return childrenNodes.reduce((result: ts.Node[], childNode: ts.Node) => {
+			return result.concat(this._findNodes(childNode, kind));
+		}, initialValue);
+	}
+
+	protected _printAllChildren(sourceFile: ts.SourceFile, node: ts.Node, depth = 0) {
+		console.log(
+			new Array(depth + 1).join('----'),
+			`[${node.kind}]`,
+			this._syntaxKindToName(node.kind),
+			`[pos: ${node.pos}-${node.end}]`,
+			':\t\t\t',
+			node.getFullText(sourceFile).trim()
+		);
+
+		depth++;
+		node.getChildren(sourceFile).forEach(childNode => this._printAllChildren(sourceFile, childNode, depth));
+	}
+
+	protected _syntaxKindToName(kind: ts.SyntaxKind) {
+		return ts.SyntaxKind[kind];
+	}
+
+}

src/parsers/function.parser.ts

@@ -0,0 +1,61 @@
+import { ParserInterface } from './parser.interface';
+import { AbstractAstParser } from './abstract-ast.parser';
+import { TranslationCollection } from '../utils/translation.collection';
+
+import * as ts from 'typescript';
+
+export class FunctionParser extends AbstractAstParser implements ParserInterface {
+
+	protected _functionIdentifier: string = '_';
+
+	public constructor(options?: any) {
+		super();
+		if (options && typeof options.identifier !== 'undefined') {
+			this._functionIdentifier = options.identifier;
+		}
+	}
+
+	public extract(contents: string, path?: string): TranslationCollection {
+		let collection: TranslationCollection = new TranslationCollection();
+
+		this._sourceFile = this._createSourceFile(path, contents);
+
+		const callNodes = this._findCallNodes();
+		callNodes.forEach(callNode => {
+			const keys: string[] = this._getCallArgStrings(callNode);
+			if (keys && keys.length) {
+				collection = collection.addKeys(keys);
+			}
+		});
+
+		return collection;
+	}
+
+	/**
+	 * Find all calls to marker function
+	 */
+	protected _findCallNodes(node?: ts.Node): ts.CallExpression[] {
+		if (!node) {
+			node = this._sourceFile;
+		}
+
+		let callNodes = this._findNodes(node, ts.SyntaxKind.CallExpression) as ts.CallExpression[];
+		callNodes = callNodes
+			.filter(callNode => {
+				// Only call expressions with arguments
+				if (callNode.arguments.length < 1) {
+					return false;
+				}
+
+				const identifier = (callNode.getChildAt(0) as ts.Identifier).text;
+				if (identifier !== this._functionIdentifier) {
+					return false;
+				}
+
+				return true;
+			});
+
+		return callNodes;
+	}
+
+}

src/parsers/service.parser.ts

@@ -1,10 +1,10 @@
 import { ParserInterface } from './parser.interface';
+import { AbstractAstParser } from './abstract-ast.parser';
 import { TranslationCollection } from '../utils/translation.collection';
-import { syntaxKindToName } from '../utils/ast-utils';
 
 import * as ts from 'typescript';
 
-export class ServiceParser implements ParserInterface {
+export class ServiceParser extends AbstractAstParser implements ParserInterface {
 
 	protected _sourceFile: ts.SourceFile;
 
@@ -33,10 +33,6 @@ export class ServiceParser implements ParserInterface {
 		return collection;
 	}
 
-	protected _createSourceFile(path: string, contents: string): ts.SourceFile {
-		return ts.createSourceFile(path, contents, null, /*setParentNodes */ false);
-	}
-
 	/**
 	 * Detect what the TranslateService instance property
 	 * is called by inspecting constructor params
@@ -91,10 +87,12 @@ export class ServiceParser implements ParserInterface {
 
 		let callNodes = this._findNodes(node, ts.SyntaxKind.CallExpression) as ts.CallExpression[];
 		callNodes = callNodes
-			// Only call expressions with arguments
-			.filter(callNode => callNode.arguments.length > 0)
-			// More filters
 			.filter(callNode => {
+				// Only call expressions with arguments
+				if (callNode.arguments.length < 1) {
+					return false;
+				}
+
 				const propAccess = callNode.getChildAt(0).getChildAt(0) as ts.PropertyAccessExpression;
 				if (!propAccess || propAccess.kind !== ts.SyntaxKind.PropertyAccessExpression) {
 					return false;
@@ -120,44 +118,4 @@ export class ServiceParser implements ParserInterface {
 		return callNodes;
 	}
 
-	/**
-	 * Get strings from function call's first argument
-	 */
-	protected _getCallArgStrings(callNode: ts.CallExpression): string[] {
-		if (!callNode.arguments.length) {
-			return;
-		}
-
-		const firstArg = callNode.arguments[0];
-		switch (firstArg.kind) {
-			case ts.SyntaxKind.StringLiteral:
-			case ts.SyntaxKind.FirstTemplateToken:
-				return [(firstArg as ts.StringLiteral).text];
-			case ts.SyntaxKind.ArrayLiteralExpression:
-				return (firstArg as ts.ArrayLiteralExpression).elements
-					.map((element: ts.StringLiteral) => element.text);
-			case ts.SyntaxKind.Identifier:
-				console.log('WARNING: We cannot extract variable values passed to TranslateService (yet)');
-				break;
-			default:
-				console.log(`SKIP: Unknown argument type: '${syntaxKindToName(firstArg.kind)}'`, firstArg);
-		}
-	}
-
-	/**
-	 * Find all child nodes of a kind
-	 */
-	protected _findNodes(node: ts.Node, kind: ts.SyntaxKind, onlyOne: boolean = false): ts.Node[] {
-		if (node.kind === kind && onlyOne) {
-			return [node];
-		}
-
-		const childrenNodes: ts.Node[] = node.getChildren(this._sourceFile);
-		const initialValue: ts.Node[] = node.kind === kind ? [node] : [];
-
-		return childrenNodes.reduce((result: ts.Node[], childNode: ts.Node) => {
-			return result.concat(this._findNodes(childNode, kind));
-		}, initialValue);
-	}
-
 }

src/utils/ast-utils.ts

@@ -1,19 +0,0 @@
-import * as ts from 'typescript';
-
-export function printAllChildren(sourceFile: ts.SourceFile, node: ts.Node, depth = 0) {
-	console.log(
-		new Array(depth + 1).join('----'),
-		`[${node.kind}]`,
-		syntaxKindToName(node.kind),
-		`[pos: ${node.pos}-${node.end}]`,
-		':\t\t\t',
-		node.getFullText(sourceFile).trim()
-	);
-
-	depth++;
-	node.getChildren(sourceFile).forEach(childNode => printAllChildren(sourceFile, childNode, depth));
-}
-
-export function syntaxKindToName(kind: ts.SyntaxKind) {
-	return ts.SyntaxKind[kind];
-}

src/utils/utils.ts

@@ -0,0 +1,5 @@
+import * as ts from 'typescript';
+
+export function _(key: string | string[]): string | string[] {
+	return key;
+}

tests/parsers/function.parser.spec.ts

@@ -0,0 +1,27 @@
+import { expect } from 'chai';
+
+import { FunctionParser } from '../../src/parsers/function.parser';
+
+describe('FunctionParser', () => {
+
+	const componentFilename: string = 'test.component.ts';
+
+	let parser: FunctionParser;
+
+	beforeEach(() => {
+		parser = new FunctionParser();
+	});
+
+
+	it('should extract strings using marker function', () => {
+		const contents = `
+			import { _ } from '@biesbjerg/ngx-translate-extract';
+			_('Hello world');
+			_(['I', 'am', 'extracted']);
+			otherFunction('But I am not');
+		`;
+		const keys = parser.extract(contents, componentFilename).keys();
+		expect(keys).to.deep.equal(['Hello world', 'I', 'am', 'extracted']);
+	});
+
+});