You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
63 lines
1.7 KiB
63 lines
1.7 KiB
'use strict';
|
|
|
|
// http://www.2ality.com/2013/10/safe-integers.html
|
|
// http://es6.ruanyifeng.com/#docs/number
|
|
exports.MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || Math.pow(2, 53) - 1;
|
|
exports.MIN_SAFE_INTEGER = -exports.MAX_SAFE_INTEGER;
|
|
var MAX_SAFE_INTEGER_STR = exports.MAX_SAFE_INTEGER_STR = String(exports.MAX_SAFE_INTEGER);
|
|
var MAX_SAFE_INTEGER_STR_LENGTH = MAX_SAFE_INTEGER_STR.length;
|
|
|
|
/**
|
|
* Detect a number string can safe convert to Javascript Number.
|
|
*
|
|
* @param {String} s number format string, like `"123"`, `"-1000123123123123123123"`
|
|
* @return {Boolean}
|
|
*/
|
|
exports.isSafeNumberString = function isSafeNumberString(s) {
|
|
if (s[0] === '-') {
|
|
s = s.substring(1);
|
|
}
|
|
if (s.length < MAX_SAFE_INTEGER_STR_LENGTH ||
|
|
(s.length === MAX_SAFE_INTEGER_STR_LENGTH && s <= MAX_SAFE_INTEGER_STR)) {
|
|
return true;
|
|
}
|
|
return false;
|
|
};
|
|
|
|
/**
|
|
* Convert string to Number if string in safe Number scope.
|
|
*
|
|
* @param {String} s number format string.
|
|
* @return {Number|String} success will return Number, otherise return the original string.
|
|
*/
|
|
exports.toSafeNumber = function toSafeNumber(s) {
|
|
if (typeof s === 'number') {
|
|
return s;
|
|
}
|
|
|
|
return exports.isSafeNumberString(s) ? Number(s) : s;
|
|
};
|
|
|
|
/**
|
|
* Produces a random integer between the inclusive `lower` and `upper` bounds.
|
|
*
|
|
* @param {Number} lower The lower bound.
|
|
* @param {Number} upper The upper bound.
|
|
* @return {Number} Returns the random number.
|
|
*/
|
|
exports.random = function random(lower, upper) {
|
|
if (lower === undefined && upper === undefined) {
|
|
return 0;
|
|
}
|
|
if (upper === undefined) {
|
|
upper = lower;
|
|
lower = 0;
|
|
}
|
|
var temp;
|
|
if (lower > upper) {
|
|
temp = lower;
|
|
lower = upper;
|
|
upper = temp;
|
|
}
|
|
return Math.floor(lower + Math.random() * (upper - lower));
|
|
};
|