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76 lines
2.0 KiB
76 lines
2.0 KiB
# `dlv(obj, keypath)` [](https://npmjs.com/package/dlv) [](https://travis-ci.org/developit/dlv) |
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> Safely get a dot-notated path within a nested object, with ability to return a default if the full key path does not exist or the value is undefined |
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### Why? |
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Smallest possible implementation: only **130 bytes.** |
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You could write this yourself, but then you'd have to write [tests]. |
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Supports ES Modules, CommonJS and globals. |
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### Installation |
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`npm install --save dlv` |
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### Usage |
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`delve(object, keypath, [default])` |
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```js |
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import delve from 'dlv'; |
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let obj = { |
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a: { |
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b: { |
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c: 1, |
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d: undefined, |
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e: null |
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} |
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} |
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}; |
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//use string dot notation for keys |
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delve(obj, 'a.b.c') === 1; |
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//or use an array key |
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delve(obj, ['a', 'b', 'c']) === 1; |
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delve(obj, 'a.b') === obj.a.b; |
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//returns undefined if the full key path does not exist and no default is specified |
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delve(obj, 'a.b.f') === undefined; |
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//optional third parameter for default if the full key in path is missing |
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delve(obj, 'a.b.f', 'foo') === 'foo'; |
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//or if the key exists but the value is undefined |
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delve(obj, 'a.b.d', 'foo') === 'foo'; |
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//Non-truthy defined values are still returned if they exist at the full keypath |
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delve(obj, 'a.b.e', 'foo') === null; |
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//undefined obj or key returns undefined, unless a default is supplied |
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delve(undefined, 'a.b.c') === undefined; |
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delve(undefined, 'a.b.c', 'foo') === 'foo'; |
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delve(obj, undefined, 'foo') === 'foo'; |
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``` |
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### Setter Counterparts |
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- [dset](https://github.com/lukeed/dset) by [@lukeed](https://github.com/lukeed) is the spiritual "set" counterpart of `dlv` and very fast. |
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- [bury](https://github.com/kalmbach/bury) by [@kalmbach](https://github.com/kalmbach) does the opposite of `dlv` and is implemented in a very similar manner. |
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### License |
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[MIT](https://oss.ninja/mit/developit/) |
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[preact]: https://github.com/developit/preact |
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[tests]: https://github.com/developit/dlv/blob/master/test.js
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