Files
lodash/.internal/createRound.js
2017-04-10 10:05:25 +02:00

26 lines
780 B
JavaScript

/**
* Creates a function like `round`.
*
* @private
* @param {string} methodName The name of the `Math` method to use when rounding.
* @returns {Function} Returns the new round function.
*/
function createRound(methodName) {
const func = Math[methodName]
return (number, precision) => {
precision = precision == null ? 0 : Math.min(precision, 292)
if (precision) {
// Shift with exponential notation to avoid floating-point issues.
// See [MDN](https://mdn.io/round#Examples) for more details.
let pair = `${number}e`.split('e')
const value = func(`${pair[0]}e${+pair[1] + precision}`)
pair = `${value}e`.split('e')
return +`${pair[0]}e${+pair[1] - precision}`
}
return func(number)
}
}
export default createRound