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| -rw-r--r-- | doc/development/fe_guide/style_guide_js.md | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/development/fe_guide/style_guide_js.md b/doc/development/fe_guide/style_guide_js.md index ed656476a96..038a689c09a 100644 --- a/doc/development/fe_guide/style_guide_js.md +++ b/doc/development/fe_guide/style_guide_js.md @@ -168,6 +168,23 @@ See [our current .eslintrc][eslintrc] for specific rules and patterns. - Avoid constructors with side-effects +- Prefer `.map`, `.reduce` or `.filter` over `.forEach` +A forEach will cause side effects, it will be mutating the array being iterated. Prefer using `.map`, +`.reduce` or `.filter` + + ```javascript + const users = [ { name: 'Foo' }, { name: 'Bar' } ]; + + // bad + users.forEach((user, index) => { + user.id = index; + }); + + // good + const usersWithId = users.map((user, index) => { + return Object.assign({}, user, { id: index }); + }); + ``` #### Parse Strings into Numbers - `parseInt()` is preferable over `Number()` or `+` |