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assign.js
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assign.js
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const isPromise = require('./_internal/isPromise')
const objectAssign = require('./_internal/objectAssign')
const __ = require('./_internal/placeholder')
const curry2 = require('./_internal/curry2')
const curry3 = require('./_internal/curry3')
const functionObjectAll = require('./_internal/functionObjectAll')
// _assign(object Object, funcs Object<function>) -> Promise|Object
const _assign = function (object, funcs) {
const result = functionObjectAll(funcs, [object])
return isPromise(result)
? result.then(curry3(objectAssign, {}, object, __))
: ({ ...object, ...result })
}
/**
* @name assign
*
* @synopsis
* ```coffeescript [specscript]
* assign(object Object, resolvers Object<function>) -> result Promise|Object
*
* assign(resolvers Object<function>)(object Object) -> result Promise|Object
* ```
*
* @description
* Function executor and composer. Accepts an object of resolver functions and an argument object. Creates a result object from the argument object, evaluates each resolver with the argument object, and assigns to the result object the evaluations at the corresponding resolver keys.
*
* ```javascript [playground]
* const assignSquaredAndCubed = assign({
* squared: ({ number }) => number ** 2,
* cubed: ({ number }) => number ** 3,
* })
*
* console.log(assignSquaredAndCubed({ number: 2 }))
* // { number: 2, squared: 4, cubed: 8 }
*
* console.log(assignSquaredAndCubed({ number: 3 }))
* // { number: 3, squared: 9, cubed: 27 }
* ```
*
* Any of the resolvers may be asynchronous and return Promises.
*
* ```javascript [playground]
* const sleep = ms => new Promise(resolve => setTimeout(resolve, ms))
*
* const asyncAssignTotal = assign({
* async total({ numbers }) {
* await sleep(500)
* return numbers.reduce((a, b) => a + b)
* },
* })
*
* asyncAssignTotal({ numbers: [1, 2, 3, 4, 5] }).then(console.log)
* // { numbers: [1, 2, 3, 4, 5], total: 15 }
* ```
*
* @execution concurrent
*/
const assign = function (arg0, arg1) {
if (arg1 == null) {
return curry2(_assign, __, arg0)
}
return isPromise(arg0)
? arg0.then(curry2(_assign, __, arg1))
: _assign(arg0, arg1)
}
module.exports = assign