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44 lines
1.2 KiB
TypeScript
44 lines
1.2 KiB
TypeScript
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// Loaded from https://deno.land/x/ramda@v0.27.2/source/lens.js
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import _curry2 from './internal/_curry2.js';
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import map from './map.js';
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/**
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* Returns a lens for the given getter and setter functions. The getter "gets"
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* the value of the focus; the setter "sets" the value of the focus. The setter
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* should not mutate the data structure.
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*
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* @func
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* @memberOf R
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* @since v0.8.0
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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 (s -> a) -> ((a, s) -> s) -> Lens s a
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* @param {Function} getter
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* @param {Function} setter
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* @return {Lens}
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* @see R.view, R.set, R.over, R.lensIndex, R.lensProp
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* @example
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*
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* const xLens = R.lens(R.prop('x'), R.assoc('x'));
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*
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* R.view(xLens, {x: 1, y: 2}); //=> 1
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* R.set(xLens, 4, {x: 1, y: 2}); //=> {x: 4, y: 2}
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* R.over(xLens, R.negate, {x: 1, y: 2}); //=> {x: -1, y: 2}
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*/
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var lens = _curry2(function lens(getter, setter) {
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return function(toFunctorFn) {
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return function(target) {
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return map(
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function(focus) {
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return setter(focus, target);
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},
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toFunctorFn(getter(target))
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);
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};
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};
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});
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export default lens;
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