dependency-cruiser/src/extract/parse/toTypescriptAST.js

Validate and visualize dependencies. With your rules. JavaScript, TypeScript, CoffeeScript. ES6, CommonJS, AMD.

"use strict";
const fs         = require('fs');
const tryRequire = require("semver-try-require");
const _memoize   = require("lodash/memoize");
const typescript = tryRequire(
    "typescript",
    require("../../../package.json").supportedTranspilers.typescript
);

/**
 * Compiles pTypescriptSource into a (typescript) AST
 *
 * @param {string} pTypescriptSource - the source to compile
 * @param {string} [pFileName] - (optional) file name the typescript
 *                              compiler can use in error messages
 * @return {object} - a (typescript) AST
 */
function getASTFromSource(pTypescriptSource, pFileName) {
    return typescript.createSourceFile(
        pFileName || '$internal-file-name',
        pTypescriptSource,
        typescript.ScriptTarget.Latest,
        false
    );
}

/**
 * Compiles the file identified by pFileName into a (typescript)
 * AST and returns it
 *
 * @param {string} pFileName - the name of the file to compile
 * @return {object} - a (typescript) AST
 */
function getAST(pFileName){
    return getASTFromSource(
        fs.readFileSync(pFileName, 'utf8'),
        pFileName
    );
}

module.exports = {
    getASTFromSource,

    /**
     * @return {boolean} - true if the typescript compiler is available,
     *                     false in all other cases
     */
    isAvailable: () => typescript !== false,

    /**
     * Compiles the file identified by pFileName into a (typescript)
     * AST and returns it. Subsequent calls for the same file name will
     * return the result from a cache
     *
     * @param {string} pFileName - the name of the file to compile
     * @return {object} - a (typescript) AST
     */
    getASTCached: _memoize(getAST)
};