34 lines
1.1 KiB
JavaScript
34 lines
1.1 KiB
JavaScript
|
import toInteger from './toInteger.js';
|
||
|
|
import toNumber from './toNumber.js';
|
||
|
|
import toString from './toString.js';
|
||
|
|
|
||
|
|
/* Built-in method references for those with the same name as other `lodash` methods. */
|
||
|
|
var nativeMin = Math.min;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* 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) {
|
||
|
|
var func = Math[methodName];
|
||
|
|
return function(number, precision) {
|
||
|
|
number = toNumber(number);
|
||
|
|
precision = precision == null ? 0 : nativeMin(toInteger(precision), 292);
|
||
|
|
if (precision) {
|
||
|
|
// Shift with exponential notation to avoid floating-point issues.
|
||
|
|
// See [MDN](https://mdn.io/round#Examples) for more details.
|
||
|
|
var pair = (toString(number) + 'e').split('e'),
|
||
|
|
value = func(pair[0] + 'e' + (+pair[1] + precision));
|
||
|
|
|
||
|
|
pair = (toString(value) + 'e').split('e');
|
||
|
|
return +(pair[0] + 'e' + (+pair[1] - precision));
|
||
|
|
}
|
||
|
|
return func(number);
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
export default createRound;
|