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🚀1K tiny & fast lib for doing addition, subtraction, multiplication and division operations precisely

JavaScript 3.07% TypeScript 96.93%

floating-point number-converter rounding-error

number-precision's Introduction

number-precision

Perform addition, subtraction, multiplication and division operations precisely using javascript

Why

0.1 + 0.2 = 0.30000000000000004
1.0 - 0.9 = 0.09999999999999998
0.105.toFixed(2) = 0.1 // not 0.11

Install

npm install number-precision --save

Methods

NP.strip(num)         // strip a number to nearest right number
NP.plus(num1, num2, num3, ...)   // addition, num + num2 + num3, two numbers is required at least.
NP.minus(num1, num2, num3, ...)  // subtraction, num1 - num2 - num3
NP.times(num1, num2, num3, ...)  // multiplication, num1 * num2 * num3
NP.divide(num1, num2, num3, ...) // division, num1 / num2 / num3
NP.round(num, ratio)  // round a number based on ratio

Usage

import NP from 'number-precision'
NP.strip(0.09999999999999998); // = 0.1
NP.plus(0.1, 0.2);             // = 0.3, not 0.30000000000000004
NP.plus(2.3, 2.4);             // = 4.7, not 4.699999999999999
NP.minus(1.0, 0.9);            // = 0.1, not 0.09999999999999998
NP.times(3, 0.3);              // = 0.9, not 0.8999999999999999
NP.times(0.362, 100);          // = 36.2, not 36.199999999999996
NP.divide(1.21, 1.1);          // = 1.1, not 1.0999999999999999
NP.round(0.105, 2);            // = 0.11, not 0.1

PS: If you want to get rid of XXX is beyond boundary when transfer to integer, the results may not be accurate, use this at the beginning of your app to turn off boundary checking.

NP.enableBoundaryChecking(false); // default param is true

License

MIT

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number-precision's Issues

why do this use precision = 15 as default value for strip function?

undefined/null校验

目前如果传入undefined/null数据，就会报错，是否可以校验传入数据的正确性

two float number plus a problem

NP.plus(8.05463959, 9.90925221) is beyond boundary when transfer to integer, the results may not be accurate

控制台warning

31941166666666700 is beyond boundary when transfer to integer, the results may not be accurate
控制台warning

With more and more projects making steps towards http 2 and using modules right in the browser (no bundling/webpack involved), an ES6 importable version (which does not rely on webpack to transpile the import) would be desirable.

增加除余操作

NP.surplus(100, 3) // 100 % 3 ==> 1

NP.times(9999999999999.46, 100)

NP.times(9999999999999.46, 100) ==> 999999999999945.9

13位9

The result is not equal to 999999999999946

0.7-0.1 is not equal 0.6

0.7*100 is not 7,is 7.000000000000001

describe('NP.minus', () => {
function check(num1, num2, result) {
assert.strictEqual(NP.minus(num1, num2), result);
}

it('can do minus operation', () => {
check(0.07, 0.01, 0.06);
});
});

warning

-3000000000000000500 is beyond boundary when transfer to integer, the results may not be accurate

怎么默认结果是保留两位小数的字符串？

NP.plus(0.1, 0.2) > 0.3 期待可以配置默认转成 '0.30'

Multiplication issue

I'm trying to multiply 9.700000042 and 1000000000 using the times method.
It should show 9700000042 as the final result. But it's returning 9700000041.999998.
please help.

strip 不生效

const NP = require("number-precision");
console.log(0.151 - 0.145);// 0.006000000000000005
console.log(NP.strip(0.151-0.145)); //0.00600000000000001

Why not add to @types/number-precision ?

两个操作数为undefined或者null会报错

计算无限循环小数的问题

NP.times(NP.times(1/3, 10), 3) // 9.999999999999998
NP.times(7/3, 3) // 7.000000000000001

这种有什么解决方案吗？

计算时数量级超过475左右会报栈溢出

以 NP.plus 为例

var data = new Array(475).fill(1)
NP.plus(...data)  // 475

var data = new Array(480).fill(1)
NP.plus(...data)  // Uncaught RangeError: Maximum call stack size exceeded

divide(4750.49269435, 4)结果错误

/**
 * 精确乘法
 */
function times(num1, num2) {
    // var num1Changed = Number(num1.toString().replace('.', ''));
    // var num2Changed = Number(num2.toString().replace('.', ''));
    // var baseNum = digitLength(num1) + digitLength(num2);
    var dl1 = digitLength(num1);
    var dl2 = digitLength(num2);
    var num1Changed = num1 * Math.pow(10, dl1);
    var num2Changed = num2 * Math.pow(10, dl2);
    var baseNum = dl1 + dl2;
    return num1Changed * num2Changed / Math.pow(10, baseNum);
}

/**
 * 精确除法
 */
function divide(num1, num2) {
    // var num1Changed = Number(num1.toString().replace('.', ''));
    // var num2Changed = Number(num2.toString().replace('.', ''));
    var dl1 = digitLength(num1);
    var dl2 = digitLength(num2);
    var num1Changed = num1 * Math.pow(10, dl1);
    var num2Changed = num2 * Math.pow(10, dl2);
    return times((num1Changed / num2Changed), Math.pow(10, dl2 - dl1));
}

能否打包时也打包打包.d.ts啊

times Calculation error

times('100.12', '100.00') === 1,001.20 . Should be 10012.00

33.3333除以100 在浏览器上计算出现问题

NP.divide(33.3333, 100) = 0.33333300000000005

times 计算问题

NP.times(9999999999999.46, 100) // 999999999999945.9

这个结果是否有问题？

使用 big.js 计算结果为 999999999999946

可以参考我写的 JS浮点数计算测试

希望能在运算效率上再加强

我做了一下压力测试，感觉效率上有改进的余地：

describe('求余数运算', () => {

//Math.round 用时14ms
it('test Math', () => {
let total=0;
for (let i = 1; i <= 10000 * 10; i++) {
total += Math.round(i * 100) / 100;
}
console.log(total);
});

//Math.round 再加上求精度，转浮点数，用时 273ms
it('test Math2', () => {
let total=0;
for (let i = 1; i <= 10000 * 10; i++) {
total += Math.round(parseFloat((i * 100).toPrecision(14))) / 100;
}
console.log(total);
});

//NP.round 用时1sec963ms
it('test NP', () => {
let total=0;
for (let i = 1; i <= 10000 * 10; i++) {
total += NP.round(i ,2) ;
}
console.log(total);
});
})

除法超出最大整型值报错

版本：1.6.0

12833333333333334 大于 Number.MAX_SAFE_INTEGER，导致报错

原始调用如下：

NP.divide(231, 18)
// Chrome：231 / 18 = 12.833333333333334

我看有个 PR 处理过这个问题，看来没修复成功

能不能像jQuery那样链式操作呢

期望

NP.plus(0.1, 0.2).times(3)// = 0.9    not 0.9000000000000001

add操作字符串计算错误

add('-1234567890123456.00', 0)得出的结果为-1234567890123456.2

参数为字符串且末尾包含空格导致计算错误

NP.times('0.1', 100); // 10
NP.times('0.1 ', 100); // 1

第一种情况是正常的计算，第二种情况计算结果异常，原因是 '0.1 ' 中末尾包含空格。

调试发现 NP 在计算参数小数位数之前没有将其先转换为数字再计算，因此空格也算在小数位数之中并且空格在进行运算的时候不会报错，因此导致 NP 静默错误。

NP 是否需要处理参数为字符串的情况？

能增加一个最多精确到多少位小数的支持吗？

比如

roundMax(1.2344, 2) // 1.23
roundMax(1.23446, 3) // 1.234
roundMax(1.2, 3) // 1.2   NOT 1.200

Beyond boundary warnings

Is there any chance to avoid these "beyond boundary" warnings?

Missing .d.ts file in packaged output, when using tsc in host program based ts 4.x may cause problem

打包产物中缺少 .d.ts 文件，在 ts 项目中直接引用的 src/index.ts 文件的类型定义，执行 tsc 会直接编译 node_module 中 number-precison 的 index.ts，可能会产生错误。

例如在使用 ts 4.x，且开启了 noUncheckedIndexedAccess 编译选项时会产生下面的报错：

node_modules/number-precision/src/index.ts:22:16 - error TS2532: Object is possibly 'undefined'.

22   const len = (eSplit[0].split('.')[1] || '').length - +(eSplit[1] || 0);
                  ~~~~~~~~~

node_modules/number-precision/src/index.ts:55:23 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

55   let res = operation(num1, num2);
                         ~~~~

node_modules/number-precision/src/index.ts:73:35 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

73   const num1Changed = float2Fixed(num1);
                                     ~~~~

node_modules/number-precision/src/index.ts:74:35 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

74   const num2Changed = float2Fixed(num2);
                                     ~~~~

node_modules/number-precision/src/index.ts:75:31 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

75   const baseNum = digitLength(num1) + digitLength(num2);
                                 ~~~~

node_modules/number-precision/src/index.ts:75:51 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

75   const baseNum = digitLength(num1) + digitLength(num2);
                                                     ~~~~

node_modules/number-precision/src/index.ts:93:53 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

93   const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2)));
                                                       ~~~~

node_modules/number-precision/src/index.ts:93:72 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

93   const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2)));
                                                                          ~~~~

node_modules/number-precision/src/index.ts:95:17 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

95   return (times(num1, baseNum) + times(num2, baseNum)) / baseNum;
                   ~~~~

node_modules/number-precision/src/index.ts:95:40 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

95   return (times(num1, baseNum) + times(num2, baseNum)) / baseNum;
                                          ~~~~

node_modules/number-precision/src/index.ts:107:53 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

107   const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2)));
                                                        ~~~~

node_modules/number-precision/src/index.ts:107:72 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

107   const baseNum = Math.pow(10, Math.max(digitLength(num1), digitLength(num2)));
                                                                           ~~~~

node_modules/number-precision/src/index.ts:108:17 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

108   return (times(num1, baseNum) - times(num2, baseNum)) / baseNum;
                    ~~~~

node_modules/number-precision/src/index.ts:108:40 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

108   return (times(num1, baseNum) - times(num2, baseNum)) / baseNum;
                                           ~~~~

node_modules/number-precision/src/index.ts:120:35 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

120   const num1Changed = float2Fixed(num1);
                                      ~~~~

node_modules/number-precision/src/index.ts:121:35 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

121   const num2Changed = float2Fixed(num2);
                                      ~~~~

node_modules/number-precision/src/index.ts:125:74 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

125   return times(num1Changed / num2Changed, strip(Math.pow(10, digitLength(num2) - digitLength(num1))));
                                                                             ~~~~

node_modules/number-precision/src/index.ts:125:94 - error TS2345: Argument of type 'string | number | undefined' is not assignable to parameter of type 'string | number'.
  Type 'undefined' is not assignable to type 'string | number'.

125   return times(num1Changed / num2Changed, strip(Math.pow(10, digitLength(num2) - digitLength(num1))));
                                                                                                 ~~~~


Found 18 errors.

因为 .ts 文件一旦被引用总会被 tsc 编译，无法被忽略，.d.ts 类型声明文件则可以被排除，因此希望可以加上类型声明文件的生成

参考：

microsoft/TypeScript#41883

divide(83.42894732749,100) = 0.8342894732748999

divide(83.42894732749,100)
0.8342894732748999

NP.plus(2.018, 0.001)

NP.plus(2.018, 0.001)
2.0189999999999997

原因是 > 2.018 * 1000
2017.9999999999998

所以简单的乘以10的n次方不能覆盖所有情况..