26 lines
779 B
JavaScript
26 lines
779 B
JavaScript
var helperNumberDecimal = require('./helperNumberDecimal')
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var toNumberString = require('./toNumberString')
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var toNumber = require('./toNumber')
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var toFixed = require('./toFixed')
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/**
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* 减法运算
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*
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* @param { Number } num1 被减数
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* @param { Number } num2 减数
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* @return {Number}
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*/
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function subtract (num1, num2) {
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var subtrahend = toNumber(num1)
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var minuend = toNumber(num2)
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var str1 = toNumberString(subtrahend)
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var str2 = toNumberString(minuend)
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var digit1 = helperNumberDecimal(str1)
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var digit2 = helperNumberDecimal(str2)
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var ratio = Math.pow(10, Math.max(digit1, digit2))
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var precision = (digit1 >= digit2) ? digit1 : digit2
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return parseFloat(toFixed((subtrahend * ratio - minuend * ratio) / ratio, precision))
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}
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module.exports = subtract
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