closure-calculate-chunks

closure-calculate-chunks

A utility to parse JS files, determine dependencies and specify which output chunk source files appear in for closure-compiler. Uses node module resolution and determines split points from dynamic import statements.

Usage:

node --preserve-symlinks node_modules/closure-calculate-chunks/index.js --entrypoint ./src/js/entry.js

Note: the node process that utilizes this library should be launched with the --preserve-symlinks option or the file paths returned may not match the path expected by node module resolution.

Flags

• --entrypoint path/toFile required. initial entrypoint to the application. This flag may occur multiple times, but the first usage will be the true entrypoint and will have the language polyfills injected by closure-compiler. All other entrypoints will have a dependence on the first entrypoint.

• --manual-entrypoint path/to/parent/chunk:path/to/entrypoint add a custom entrypoint for code that is not discoverable.

• --closure-library-base-js-path path/to/google-closure-library/closure/goog/base.js path to closure-library's base.js file

• --deps-file path/to/closure/deps.js This flag may occur multiple times.

• --extra-deps namespace:path/to/providing/src This flag may occur multiple times.

• --package-json-entry-names field1,field2,... Ordered list of entries to look for in package.json files when resolving modules.

• --visualize Instead of outputting the closure compiler flags, open an HTML page to visualize the graph.

Output

Outputs a JSON object with closure-compiler chunk definitions and source files in dependency order.

{
  "chunk": [
    "baseChunkName:numFiles",
    "childChunkName:numFiles:baseChunkName"
  ],
  "sources": [
    "file1.js",
    "file2.js"
  ]
}

Why Sources End Up in Other Chunks

Closure Compiler will not duplicate code. If a source file is utilized in more than one output chunk, this utility will hoist the file up into the lowest common ancestor which is common to all paths.