ifchanged
Conditionally run a command if watched files have changed, for instance:
ifchanged yarn build
Running the above multiple times will only result in executing 'yarn build' if a source file has changed since last run, otherwise it is a noop.
To specify which files to watch:
ifchanged --watch="src/**/*.js"
If multiple steps depend on whether the files have changed:
ifchanged --step=build yarn build
ifchanged --step=build:docs yarn build:docs
To provide flags to the command, use '--' to separate them from flags to ifchanged:
ifchanged --step=build -- yarn run build --step=docs
Options:
--help Show help [boolean]
--version Show version number [boolean]
--watch, -w Pattern to watch for changes using glob syntax.
[default: ["src/**/*.js","tests/**/*.js","node_modules/**/package.json"]]
--rootDir, -r Root directory to watch.
[default: "/home/mike/Private/ifchanged"]
--cache, -c Path to save internal ifchanged data to.
[default: "/home/mike/Private/ifchanged/.ifchanged_cache"]
--step, -s Step name. Makes it possible to run several steps when the
watched files have changed. [string]
--config Path to JSON config file
[default: "/home/mike/Private/ifchanged/.ifchanged.json"]
CAVEATS
Watching different file sets
Providing different '--watch' settings between runs won't work as expected unless a different '--cache' is provided as well:
ifchanged --watch=src/*.js yarn build
ifchanged --watch=docs/*.mdx yarn build:docs
The above will not work since the same cache is being used to watch two different sets of files. To get the expected result, provide a different cache to at least one of the calls:
ifchanged --watch=src/*.js yarn build
ifchanged --watch=docs/*.mdx --cache=.ifchanged-docs yarn build:docs
Sub-second changes
To optimize for performance, ifchanged only uses file modification times and sizes to check if a new run is required. Since mtime only has a resolution of seconds, ifchange can't detect changes where it is being run with a second or less between each run.
Developing
Download and run tests
git clone git@github.com:karnov/ifchanged
cd ifchanged
yarn
yarn test
Publishing
yarn publish
Remember to log in first. If publishing fails, make sure that you have access to the karnov organization at npmjs.com.
Reporting bugs
https://github.com/karnov/ifchanged/issues
Author
Michael Zedeler michael@zedeler.dk.
Copyright and license
Copyright Karnov Group A/S 2018, licensed under MIT license.