node.js api

The short way

var webpack = require("webpack");
webpack({
	// configuration
}, function(err, stats) {
	// ...
});

The long way

var webpack = require("webpack");

var compiler = webpack({
	// configuration
});

compiler.run(function(err, stats) {
	// ...
});

compiler.watch(/* watchDelay= */200, function(err, stats) {
	// ...
});

Note: watch will automatically run an initial build, so you should either call run or watch.

stats

The Stats object expose this methods:

stats.hasErrors

Returns true if there were errors while compiling.

stats.hasWarnings

Returns true if there were errors while compiling.

stats.toJson(options)

Return information as json object

You can specify the information by the options argument: (Boolean)

options.hash add the hash of the compilation

options.version add webpack version information

options.timings add timing information

options.assets add assets information

options.chunks add chunk information

options.chunkModules add built modules information to chunk information

options.modules add built modules information

options.cached add also information about cached (not built) modules

options.reasons add information about the reasons why modules are included

options.source add the source code of modules

options.errorDetails add details to errors (like resolving log)

options.chunkOrigins add the origins of chunks and chunk merging info

options.modulesSort (string) sort the modules by that field

options.chunksSort (string) sort the chunks by that field

options.assetsSort (string) sort the assets by that field

In toJson every flag defaults to true (except chunkModules). By default it's not sorted.

Here is an example of the resulting JSON.

stats.toString(options)

Returns a formatted string of the result.

options are the same as options in toJson.

options.colors With console colors

error handling

to handle all errors and warnings with the node.js API you need to test err, stats.errors and stats.warnings:

var webpack = require("webpack");
webpack({
	// configuration
}, function(err, stats) {
	if(err)
		return handleFatalError(err);
	var jsonStats = stats.toJson();
	if(jsonStats.errors.length > 0)
		return handleSoftErrors(jsonStats.errors);
	if(jsonStats.warnings.length > 0)
		handleWarnings(jsonStats.warnings);
	successfullyCompiled();
});