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We serve JavaScript to any browser that supports fetch. We use esbuild to transpile and minify our JavaScript.
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We prefix CSS for every browser in our browserslist. We use autoprefixer to add vendor-specific prefixes to rules where necessary.
Within the root directory, run npx browserslist to output the set of browser
targets given to autoprefixer (CSS) transpiling.
!!! note
A browserslist string is used in `package.json`.
See the
[browserslist docs](https://github.com/browserslist/browserslist#full-list)
for information on this string and the defaults.
For JavaScript, esbuild uses the es6 target and
our code conditionally includes JavaScript in browsers that
support fetch.
!!! note
JavaScript may still
be delivered to legacy browsers in the form of our analytics and
related scripts.
Twice per year we aim to updated the browser metrics that are fed into our browserslist config at @cfpb/browserslist-config.
Per the best practices published by browserslist, we use a 0.2% cutoff with this config for the browsers that get fed into our build systems.
However, for what we actively aim to support and test, we use a higher cutoff of 1%. The current 1% cutoff list is:
and_chr 131
chrome 130
chrome 129
chrome 128
chrome 127
chrome 126
chrome 125
edge 127
edge 126
ios_saf 18.0
ios_saf 17.6
ios_saf 17.5
safari 17.6
safari 17.5