@343dev/harold

Harold is a CLI tool that compares frontend project bundles in size.

По-русски

Rationale

The bundle size of an average frontend project grows on every change.

To feel the pain To make it easier to measure & compare the project size while refactoring or updating the deps, we've built Harold.

Demo

The demo is accelerated. In real life setting up the dependencies and building a project takes forever.

Installation

npm install -g @343dev/harold

Commands

snapshot [options]

Builds the project and takes the snapshot.

Available options:

• -c, --config <path> — use this configuration, overriding default config options if present;
• -o, --output <path> — sets the snapshot output path; default is harold_snapshot_<date>_<time>.json;
• -e, --exec <cmd> — sets the building command; default is npm run build-production;
• -p, --path <path> — sets the path of the build result directory, which will be used for snapshotting; default is public.

diff <left> <right>

Compares the passed snapshots.

help

Sends halp.

Configuration

The default settings are located in .haroldrc.js, the file contains a list of supported parameters and their brief description.

When running with the --config path/to/.haroldrc.js flag, the settings from the specified configuration file will be used.

When running normally, without the --config flag, a recursive search for the .haroldrc.js file will be performed starting from the current directory and up to the root of the file system. If the file is not found, the default settings will be applied.

FAQ

How does it work?

When you take a snapshot, Harold runs the build command, waits until the project is building, then goes to the output directory and records the files' sizes. At the same time it creates the gzipped version of each file and records it's size too. After than it spits the snapshot — JSON file with all the data.

Then, when you have two snapshots and run harold diff first.json second.json it compares the diff files and prints the overall comparison.

Usage example

# Open your project folder
$ cd ~/my-syper-kewl-project/

# Take the first snapshot
$ harold snapshot -o before.json

# Make some changes in the project

# Take the second snapshot
$ harold snapshot -o after.json

# Compare them
$ harold diff before.json after.json

Snapshots:
 Left: 11/10/2020 6:30:56 PM • my-syper-kewl-project • master
 Right: 11/10/2020 6:45:13 PM • my-syper-kewl-project • improvement/framework-update

Build time:
 16 seconds slower (Left: 129 seconds, Right: 145 seconds)

Diff by category:
 ————————————————————————————————————————————————————————————————————————————————————
                before              after               Changes
 ————————————————————————————————————————————————————————————————————————————————————
  JS            1.04 MB (270 kB)    1.12 MB (294 kB)    +78.2 kB (+23.7 kB), +1 item
 ————————————————————————————————————————————————————————————————————————————————————
  JS (legacy)   1.07 MB (285 kB)    1.16 MB (314 kB)    +90.6 kB (+28.6 kB), +1 item
 ————————————————————————————————————————————————————————————————————————————————————
  CSS           144 kB (23.4 kB)    144 kB (23.4 kB)    No changes
 ————————————————————————————————————————————————————————————————————————————————————
  Images        5.26 MB (5.23 MB)   5.26 MB (5.23 MB)   No changes
 ————————————————————————————————————————————————————————————————————————————————————
  Fonts         159 kB (159 kB)     159 kB (159 kB)     No changes
 ————————————————————————————————————————————————————————————————————————————————————
  Videos        1.59 MB (1.58 MB)   1.59 MB (1.58 MB)   No changes
 ————————————————————————————————————————————————————————————————————————————————————
  Other         127 kB (13.2 kB)    127 kB (13.3 kB)    +364 B (+82 B)
 ————————————————————————————————————————————————————————————————————————————————————

  Total         9.4 MB (7.56 MB)    9.57 MB (7.61 MB)   +169 kB (+52.4 kB), +2 items
 ————————————————————————————————————————————————————————————————————————————————————

Diff by files:
 m public: +169 kB (+52.4 kB)
 m public/10.js: +16 B (+4 B)
 m public/11.js: -20 B (-3 B)
 + public/12.js: 301 B (143 B)
 m public/3.js: +1.84 kB (+621 B)
 m public/app.js: +4.18 kB (+843 B)
 m public/legacy.10.js: +42 B (+18 B)
 + public/legacy.12.js: 513 B (148 B)
 m public/legacy.3.js: +1.9 kB (+634 B)
 m public/legacy.app.js: +6.83 kB (+1 kB)
 m public/legacy.vendor.js: +81.3 kB (+26.8 kB)
 m public/legacy.vendor.js.LICENSE: +182 B (+41 B)
 m public/vendor.js: +72.2 kB (+22.1 kB)
 m public/vendor.js.LICENSE: +182 B (+41 B)

How to deal with hashes in filenames?

Modern frontend bundlers may add hashes to the filenames to improve caching. But Harold compares files using their names. To improve the diff quality you can set up your bundler the way that turns off hashes when environment variable NO_HASH is set.

How to make a snapshot without building a project?

Pass to --exec a fake command, such as echo.

Credits

The avatar for the project was made by Igor Garybaldi.