32 lines
826 B
JavaScript
32 lines
826 B
JavaScript
import _curry1 from "./internal/_curry1.js";
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import lens from "./lens.js";
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import nth from "./nth.js";
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import update from "./update.js";
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/**
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* Returns a lens whose focus is the specified index.
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*
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* @func
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* @memberOf R
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* @since v0.14.0
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* @category Object
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* @typedefn Lens s a = Functor f => (a -> f a) -> s -> f s
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* @sig Number -> Lens s a
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* @param {Number} n
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* @return {Lens}
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* @see R.view, R.set, R.over, R.nth
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* @example
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*
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* const headLens = R.lensIndex(0);
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*
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* R.view(headLens, ['a', 'b', 'c']); //=> 'a'
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* R.set(headLens, 'x', ['a', 'b', 'c']); //=> ['x', 'b', 'c']
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* R.over(headLens, R.toUpper, ['a', 'b', 'c']); //=> ['A', 'b', 'c']
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*/
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var lensIndex =
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/*#__PURE__*/
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_curry1(function lensIndex(n) {
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return lens(nth(n), update(n));
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});
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export default lensIndex; |