| 1 | # shallowequal [](https://travis-ci.org/dashed/shallowequal) [](https://npmjs.com/shallowequal) [](https://www.npmjs.com/package/shallowequal)
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| 2 |
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| 3 | > `shallowequal` is like lodash's [`isEqual`](https://lodash.com/docs/3.10.1#isEqual) (v3.10.1) but for shallow (strict) equal.
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| 4 |
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| 5 | `shallowequal(value, other, [customizer], [thisArg])`
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| 6 |
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| 7 | Performs a **_shallow equality_** comparison between two values (i.e. `value` and `other`) to determine if they are equivalent.
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| 8 |
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| 9 | The equality check returns true if `value` and `other` are already strictly equal, OR when all the following are true:
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| 10 |
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| 11 | - `value` and `other` are both objects with the same keys
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| 12 | - For each key, the value in `value` and `other` are **strictly equal** (`===`)
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| 13 |
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| 14 | If `customizer` (expected to be a function) is provided it is invoked to compare values. If `customizer` returns `undefined` (i.e. `void 0`), then comparisons are handled by the `shallowequal` function instead.
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| 15 |
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| 16 | The `customizer` is bound to `thisArg` and invoked with three arguments: `(value, other, key)`.
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| 17 |
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| 18 | **NOTE:** Docs are (shamelessly) adapted from [lodash's v3.x docs](https://lodash.com/docs/3.10.1#isEqual)
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| 19 |
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| 20 | ## Install
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| 21 |
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| 22 | ```sh
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| 23 | $ yarn add shallowequal
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| 24 | # npm v5+
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| 25 | $ npm install shallowequal
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| 26 | # before npm v5
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| 27 | $ npm install --save shallowequal
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| 28 | ```
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| 29 |
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| 30 | ## Usage
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| 31 |
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| 32 | ```js
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| 33 | const shallowequal = require("shallowequal");
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| 34 |
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| 35 | const object = { user: "fred" };
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| 36 | const other = { user: "fred" };
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| 37 |
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| 38 | object == other;
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| 39 | // → false
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| 40 |
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| 41 | shallowequal(object, other);
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| 42 | // → true
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| 43 | ```
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| 44 |
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| 45 | ## Credit
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| 46 |
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| 47 | Code for `shallowEqual` originated from https://github.com/gaearon/react-pure-render/ and has since been refactored to have the exact same API as `lodash.isEqualWith` (as of `v4.17.4`).
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| 48 |
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| 49 | ## Development
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| 50 |
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| 51 | - `node.js` and `npm`. See: https://github.com/creationix/nvm#installation
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| 52 | - `yarn`. See: https://yarnpkg.com/en/docs/install
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| 53 | - `npm` dependencies. Run: `yarn install`
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| 54 |
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| 55 | ### Chores
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| 56 |
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| 57 | - Lint: `yarn lint`
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| 58 | - Test: `yarn test`
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| 59 | - Pretty: `yarn pretty`
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| 60 | - Prepare: `yarn prepare`
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| 61 |
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| 62 | ## License
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| 63 |
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| 64 | MIT.
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