TypescriptAPIUtils: add appendImport function

Author: davidkudera

packages/typescript-api-utils/sourceFiles/appendImport.ts

@@ -0,0 +1,90 @@
+import {clone, exists, find} from '@slicky/utils';
+import {findNodesByType} from './findNodesByType';
+import * as ts from 'typescript';
+
+
+export function appendImport(moduleSpecifier: string, propertyName: string|undefined, name: string, sourceFile: ts.SourceFile): string
+{
+	const imports = findNodesByType<ts.ImportDeclaration>(ts.SyntaxKind.ImportDeclaration, sourceFile);
+	const pos = imports.length ? (sourceFile.statements.indexOf(imports[imports.length - 1]) || 0) : 0;
+
+	const existingImport: ts.ImportDeclaration = find(imports, (existingImport: ts.ImportDeclaration) => {
+		return (
+			exists(existingImport.importClause) &&
+			exists(existingImport.importClause.namedBindings) &&
+			ts.isNamedImports(existingImport.importClause.namedBindings) &&
+			ts.isStringLiteral(existingImport.moduleSpecifier) &&
+			(<ts.StringLiteral>existingImport.moduleSpecifier).text === moduleSpecifier
+		);
+	});
+
+	if (existingImport) {
+		const namedBindings = <ts.NamedImports>existingImport.importClause.namedBindings;
+		const elements = clone(namedBindings.elements);
+
+		const existingElement: ts.ImportSpecifier = find(elements, (existingElement: ts.ImportSpecifier) => {
+			return (
+				(<ts.Identifier>existingElement.name).text === name ||
+				(
+					exists(existingElement.propertyName) &&
+					(<ts.Identifier>existingElement.propertyName).text === name
+				) ||
+				(
+					exists(propertyName) &&
+					exists(existingElement.propertyName) &&
+					(<ts.Identifier>existingElement.propertyName).text === propertyName
+				) ||
+				(
+					!exists(existingElement.propertyName) &&
+					exists(propertyName) &&
+					(<ts.Identifier>existingElement.name).text === propertyName
+				)
+			);
+		});
+
+		if (existingElement) {
+			if (exists(propertyName) && exists(existingElement.propertyName) && propertyName !== (<ts.Identifier>existingElement.propertyName).text) {
+				throw new Error(`appendImport: can not append new import {${propertyName} as ${name}}. File already contains import with the same name {${(<ts.Identifier>existingElement.propertyName).text} as ${(<ts.Identifier>existingElement.name).text}}.`);
+			}
+
+			return (<ts.Identifier>existingElement.name).text;
+
+		} else {
+			elements.push(createNewImportSpecifier(propertyName, name));
+			namedBindings.elements = elements;
+		}
+
+	} else {
+		const statements = clone(sourceFile.statements);
+
+		statements.splice(pos, 0, createNewImportDeclaration(moduleSpecifier, propertyName, name));
+		sourceFile.statements = statements;
+	}
+
+	return name;
+}
+
+
+function createNewImportDeclaration(moduleSpecifier: string, propertyName: string|undefined, name: string): ts.ImportDeclaration
+{
+	return ts.createImportDeclaration(
+		[],
+		[],
+		ts.createImportClause(
+			undefined,
+			ts.createNamedImports([
+				createNewImportSpecifier(propertyName, name),
+			]),
+		),
+		ts.createLiteral(moduleSpecifier),
+	);
+}
+
+
+function createNewImportSpecifier(propertyName: string|undefined, name: string): ts.ImportSpecifier
+{
+	return ts.createImportSpecifier(
+		exists(propertyName) ? ts.createIdentifier(propertyName) : undefined,
+		ts.createIdentifier(name),
+	);
+}

packages/typescript-api-utils/sourceFiles/index.ts

@@ -1,3 +1,4 @@
+export * from './appendImport';
 export * from './findNode';
 export * from './findLastNodeOfType';
 export * from './findNodesByType';

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/invalid_1.ts

@@ -0,0 +1 @@
+import {A1 as B} from '/import';

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_1.original.ts

@@ -0,0 +1 @@
+import { A } from "/import";

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_1.updated.ts

@@ -0,0 +1 @@
+import {A} from '/import';

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_2.original.ts

@@ -0,0 +1 @@
+import { A, B } from "/import";

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_2.updated.ts

@@ -0,0 +1 @@
+import {A} from '/import';

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_3.original.ts

@@ -0,0 +1 @@
+import { A } from "/import";

packages/typescript-api-utils/tests/data/sourceFiles/appendImport/valid_3.updated.ts

@@ -0,0 +1 @@
+import {A as B} from '/import';