gulp-elm

0.8.2 verified Fri May 01 auth: no javascript maintenance

Gulp plugin to compile Elm files using the Elm compiler. Version 0.8.2 supports Elm 0.19 only; earlier versions (0.7.x) support Elm 0.18. The plugin wraps Vinyl streams, providing `elm.make()` for single files and `elm.bundle()` for multiple entry files. Key options include `optimize`, `debug`, `cwd`, and custom `elm` binary path. Differentiators: simple integration with Gulp, bundle mode, and support for `--optimize` and `--debug` flags. Release cadence is sporadic, last updated in 2019.

Common errors

error Error: elm-make exited with code 1 ↓

cause Elm compilation error, possibly due to missing dependencies or syntax errors.

fix

Run elm make manually to see full error output, or check elm.json and source files.

error TypeError: elm is not a function ↓

cause Misunderstanding default import: using elm() instead of elm.make() or elm.bundle().

fix

Use elm.make(options) or elm.bundle(output, options) directly.

error Cannot find module 'gulp-elm' ↓

cause Package not installed or missing in node_modules.

fix

Run npm install gulp-elm --save-dev.

error The output file must be a string for elm.bundle() ↓

cause Missing or invalid output file argument to bundle.

fix

Pass a string as the first argument: elm.bundle('output.js', options).

Warnings

breaking Version 0.8.0 drops support for Elm 0.18 and earlier; use 0.7.x for those versions. ↓

fix For Elm 0.18, install gulp-elm@0.7.3.

gotcha The `cwd` option must point to the directory containing elm.json, not the source files. ↓

fix Set cwd to the project root, e.g., { cwd: './src' } if elm.json is there.

deprecated The `warn` option was removed in version 0.8.0. ↓

fix Use elm-make's native warning output; warnings appear on stderr.

gotcha Using `elm()` without specifying `make` or `bundle` is deprecated; use `elm.make()` explicitly. ↓

fix Always call elm.make() or elm.bundle() directly.

breaking Error messages changed format in 0.8.2; parsing errors may differ. ↓

fix Do not rely on exact error string formatting; check for error existence.

Install

npm install gulp-elm

yarn add gulp-elm

pnpm add gulp-elm

Imports

default
wrong
```
const elm = require('gulp-elm')
```
correct
```
import elm from 'gulp-elm'
```
Default import returns an object with `make` and `bundle` methods. CommonJS require works but ESM is preferred.

make

wrong

const make = require('gulp-elm').make

correct

import { make } from 'gulp-elm'

Named export for the compile function.

bundle
```
import { bundle } from 'gulp-elm'
```
Named export for the bundling function.

Quickstart

Shows basic usage of elm.make() and elm.bundle() with Gulp, including optimize option.

import gulp from 'gulp';
import elm from 'gulp-elm';

gulp.task('elm', () => {
  return gulp.src('src/Main.elm')
    .pipe(elm.make({ optimize: true }))
    .pipe(gulp.dest('dist/'));
});

gulp.task('elm-bundle', () => {
  return gulp.src('src/**/Main.elm')
    .pipe(elm.bundle('bundle.js', { optimize: true }))
    .pipe(gulp.dest('dist/'));
});