¶Ô±ÈÐÂÎļþ |
| | |
| | | let _boundaryCheckingState = true; // æ¯å¦è¿è¡è¶çæ£æ¥çå
¨å±å¼å
³ |
| | | |
| | | /** |
| | | * æéè¯¯çæ°æ®è½¬æ£ |
| | | * @private |
| | | * @example strip(0.09999999999999998)=0.1 |
| | | */ |
| | | function strip(num, precision = 15) { |
| | | return +parseFloat(Number(num).toPrecision(precision)); |
| | | } |
| | | |
| | | /** |
| | | * Return digits length of a number |
| | | * @private |
| | | * @param {*number} num Input number |
| | | */ |
| | | function digitLength(num) { |
| | | // Get digit length of e |
| | | const eSplit = num.toString().split(/[eE]/); |
| | | const len = (eSplit[0].split('.')[1] || '').length - +(eSplit[1] || 0); |
| | | return len > 0 ? len : 0; |
| | | } |
| | | |
| | | /** |
| | | * æå°æ°è½¬ææ´æ°,妿æ¯å°æ°åæ¾å¤§ææ´æ° |
| | | * @private |
| | | * @param {*number} num è¾å
¥æ° |
| | | */ |
| | | function float2Fixed(num) { |
| | | if (num.toString().indexOf('e') === -1) { |
| | | return Number(num.toString().replace('.', '')); |
| | | } |
| | | const dLen = digitLength(num); |
| | | return dLen > 0 ? strip(Number(num) * Math.pow(10, dLen)) : Number(num); |
| | | } |
| | | |
| | | /** |
| | | * æ£æµæ°åæ¯å¦è¶çï¼å¦æè¶çç»åºæç¤º |
| | | * @private |
| | | * @param {*number} num è¾å
¥æ° |
| | | */ |
| | | function checkBoundary(num) { |
| | | if (_boundaryCheckingState) { |
| | | if (num > Number.MAX_SAFE_INTEGER || num < Number.MIN_SAFE_INTEGER) { |
| | | console.warn(`${num} è¶
åºäºç²¾åº¦éå¶ï¼ç»æå¯è½ä¸æ£ç¡®`); |
| | | } |
| | | } |
| | | } |
| | | |
| | | /** |
| | | * æé彿使平è¿ä»£å |
| | | * @param {number[]} arr è¦æä½çæ°åæ°ç» |
| | | * @param {function} operation è¿ä»£æä½ |
| | | * @private |
| | | */ |
| | | function iteratorOperation(arr, operation) { |
| | | const [num1, num2, ...others] = arr; |
| | | let res = operation(num1, num2); |
| | | |
| | | others.forEach((num) => { |
| | | res = operation(res, num); |
| | | }); |
| | | |
| | | return res; |
| | | } |
| | | |
| | | /** |
| | | * é«ç²¾åº¦ä¹æ³ |
| | | * @export |
| | | */ |
| | | export function times(...nums) { |
| | | if (nums.length > 2) { |
| | | return iteratorOperation(nums, times); |
| | | } |
| | | |
| | | const [num1, num2] = nums; |
| | | const num1Changed = float2Fixed(num1); |
| | | const num2Changed = float2Fixed(num2); |
| | | const baseNum = digitLength(num1) + digitLength(num2); |
| | | const leftValue = num1Changed * num2Changed; |
| | | |
| | | checkBoundary(leftValue); |
| | | |
| | | return leftValue / Math.pow(10, baseNum); |
| | | } |
| | | |
| | | /** |
| | | * é«ç²¾åº¦å æ³ |
| | | * @export |
| | | */ |
| | | export function plus(...nums) { |
| | | if (nums.length > 2) { |
| | | return iteratorOperation(nums, plus); |
| | | } |
| | | |
| | | const [num1, num2] = nums; |
| | | // åæå¤§çå°æ°ä½ |
| | | const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2))); |
| | | // æå°æ°é½è½¬ä¸ºæ´æ°ç¶ååè®¡ç® |
| | | return (times(num1, baseNum) + times(num2, baseNum)) / baseNum; |
| | | } |
| | | |
| | | /** |
| | | * é«ç²¾åº¦åæ³ |
| | | * @export |
| | | */ |
| | | export function minus(...nums) { |
| | | if (nums.length > 2) { |
| | | return iteratorOperation(nums, minus); |
| | | } |
| | | |
| | | const [num1, num2] = nums; |
| | | const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2))); |
| | | return (times(num1, baseNum) - times(num2, baseNum)) / baseNum; |
| | | } |
| | | |
| | | /** |
| | | * é«ç²¾åº¦é¤æ³ |
| | | * @export |
| | | */ |
| | | export function divide(...nums) { |
| | | if (nums.length > 2) { |
| | | return iteratorOperation(nums, divide); |
| | | } |
| | | |
| | | const [num1, num2] = nums; |
| | | const num1Changed = float2Fixed(num1); |
| | | const num2Changed = float2Fixed(num2); |
| | | checkBoundary(num1Changed); |
| | | checkBoundary(num2Changed); |
| | | // éè¦ï¼è¿éå¿
é¡»ç¨stripè¿è¡ä¿®æ£ |
| | | return times(num1Changed / num2Changed, strip(Math.pow(10, digitLength(num2) - digitLength(num1)))); |
| | | } |
| | | |
| | | /** |
| | | * åèäºå
¥ |
| | | * @export |
| | | */ |
| | | export function round(num, ratio) { |
| | | const base = Math.pow(10, ratio); |
| | | let result = divide(Math.round(Math.abs(times(num, base))), base); |
| | | if (num < 0 && result !== 0) { |
| | | result = times(result, -1); |
| | | } |
| | | // 使°ä¸è¶³åè¡¥0 |
| | | return result; |
| | | } |
| | | |
| | | /** |
| | | * æ¯å¦è¿è¡è¾¹çæ£æ¥ï¼é»è®¤å¼å¯ |
| | | * @param flag æ è®°å¼å
³ï¼true 为å¼å¯ï¼false 为å
³éï¼é»è®¤ä¸º true |
| | | * @export |
| | | */ |
| | | export function enableBoundaryChecking(flag = true) { |
| | | _boundaryCheckingState = flag; |
| | | } |
| | | |
| | | |
| | | export default { |
| | | times, |
| | | plus, |
| | | minus, |
| | | divide, |
| | | round, |
| | | enableBoundaryChecking, |
| | | }; |
| | | |