google-closure-compiler basic process example

Question

could anyone please add a snippet to a google-closure-compiler basic process, I am trying unsuccessfully to this via js code. I am using the exmple snippet from the official npm page. when I run it, something seem to happen but the output file isn't created.

My code:

const ClosureCompiler = require('google-closure-compiler').jsCompiler;

console.log(ClosureCompiler.CONTRIB_PATH); // absolute path to the contrib folder which contains externs

const closureCompiler = new ClosureCompiler({
  compilation_level: 'ADVANCED'
});

const compilerProcess = closureCompiler.run([{
 path: './',
 src: 'a.js',
 sourceMap: null // optional input source map
}], (exitCode, stdOut, stdErr) => {
    console.log(stdOut)
  //compilation complete
});

Answer 1

Building from what you had, I've changed just a few things:

1) The src attribute is not a path it is the file: read the file in this case with fs.readFileSync.

2) The output is returned in the callback: you'll need to write it to the disk.

Files:

index.js

const ClosureCompiler = require('google-closure-compiler').jsCompiler;
const {writeFile, readFileSync} = require('fs');

const closureCompiler = new ClosureCompiler({
  compilation_level: 'ADVANCED'
});
let src = readFileSync('a.js', 'UTF-8');
const compilerProcess = closureCompiler.run([{
 path: './',
 src: src,
 sourceMap: null
}], (exitCode, stdOut, stdErr) => {
  stdOut.map((fileResults) => {
    writeFile(fileResults.path, fileResults.src, () => {});
  });
});

a.js

console.log('hello world!')

compiled.js

console.log("hello world!");