Fix sourcemaps

package.json

@@ -102,6 +102,7 @@
  "rollup-plugin-commonjs": "^8.2.6",
  "rollup-plugin-flow": "^1.1.1",
  "rollup-plugin-node-resolve": "3.0.0",
+ "rollup-plugin-sourcemaps": "^0.4.2",
  "rollup-plugin-uglify": "^3.0.0",
  "sinon": "^2.1.0",
  "slugg": "^1.2.1",

rollup.config.js

@@ -7,17 +7,19 @@ import json from 'rollup-plugin-json';
 import browserifyPlugin from 'rollup-plugin-browserify-transform';
 import brfs from 'brfs';
 import uglify from 'rollup-plugin-uglify'
+import sourcemaps from 'rollup-plugin-sourcemaps';
 import minifyStyleSpec from './build/rollup_plugin_minify_style_spec';
 
 const production = process.env.BUILD === 'production';
 const outputFile = production ? 'dist/mapbox-gl.js' : 'dist/mapbox-gl-dev.js';
 
 const plugins = [
- flow(),
+ sourcemaps(),
+ flow({pretty: true}), // setting {pretty: true} works around https://github.com/leebyron/rollup-plugin-flow/issues/5
  minifyStyleSpec(),
  json(),
  buble({transforms: {dangerousForOf: true}, objectAssign: "Object.assign"}),
- unassert(),
+ production ? unassert() : false,
  resolve({
  browser: true,
  preferBuiltins: false
@@ -29,12 +31,9 @@ const plugins = [
  namedExports: {
  '@mapbox/gl-matrix': ['vec3', 'vec4', 'mat2', 'mat3', 'mat4']
  }
- })
-]
-
-if (production) {
- plugins.push(uglify());
-}
+ }),
+ production ? uglify() : false
+].filter(Boolean)
 
 const config = [{
  input: ['src/index.js', 'src/source/worker.js'],
@@ -54,7 +53,7 @@ const config = [{
  format: 'umd',
  sourcemap: production ? true : 'inline'
  },
- plugins: production ? [] : [uglify()],
+ plugins: production ? [sourcemaps(), uglify()] : [sourcemaps()],
  intro: `
 let shared, worker, mapboxgl;
 function define(_, module) {

yarn.lock

@@ -8632,6 +8632,13 @@ rollup-plugin-node-resolve@3.0.0:
  is-module "^1.0.0"
  resolve "^1.1.6"
 
+rollup-plugin-sourcemaps@^0.4.2:
+ version "0.4.2"
+ resolved "https://registry.yarnpkg.com/rollup-plugin-sourcemaps/-/rollup-plugin-sourcemaps-0.4.2.tgz#62125aa94087aadf7b83ef4dfaf629b473135e87"
+ dependencies:
+ rollup-pluginutils "^2.0.1"
+ source-map-resolve "^0.5.0"
+
 rollup-plugin-uglify@^3.0.0:
  version "3.0.0"
  resolved "https://registry.yarnpkg.com/rollup-plugin-uglify/-/rollup-plugin-uglify-3.0.0.tgz#a34eca24617709c6bf1778e9653baafa06099b86"