41 lines
886 B
JavaScript
41 lines
886 B
JavaScript
import freeze from './freeze'
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/**
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* Returns a function that always returns the supplied value.
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*
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* Useful for replacing an object outright rather than merging it.
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*
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* @function
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* @sig a -> (* -> a)
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* @memberOf u
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* @param {*} value what to return from returned function.
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* @return {function} a new function that will always return value.
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*
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* @example
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* var alwaysFour = u.constant(4);
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* expect(alwaysFour(32)).toEqual(4);
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*
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* @example
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* var user = {
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* name: 'Mitch',
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* favorites: {
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* band: 'Nirvana',
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* movie: 'The Matrix'
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* }
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* };
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*
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* var newFavorites = {
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* band: 'Coldplay'
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* };
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*
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* var result = u({ favorites: u.constant(newFavorites) }, user);
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*
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* expect(result).toEqual({ name: 'Mitch', favorites: { band: 'Coldplay' } });
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*/
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function constant(value) {
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const frozen = freeze(value)
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return () => frozen
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}
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export default constant
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