@techmely/utils/numberRoundPrecision.js

Collection of helpful JavaScript / TypeScript utils

'use strict';

/*!
 * @techmely/utils
 * Copyright(c) 2021-2024 Techmely <techmely.creation@gmail.com>
 * MIT Licensed
 */


// src/isNumber.ts
function isNumber(val) {
  return toString.call(val) === "[object Number]";
}
function checkBoundaryPrecision(num) {
  {
    if (num > Number.MAX_SAFE_INTEGER || num < Number.MIN_SAFE_INTEGER) {
      console.warn(
        `${num} is beyond boundary when transfer to integer, the results may not be accurate`
      );
    }
  }
}

// src/numberCreateOperationPrecision.ts
function createOperationPrecision(operation) {
  return (...nums) => {
    const [first, ...others] = nums;
    return others.reduce((prev, next) => operation(prev, next), first);
  };
}

// src/numberDigitLengthPrecision.ts
function digitLengthPrecision(num) {
  const eSplit = num.toString().split(/[eE]/);
  const len = (eSplit[0].split(".")[1] || "").length - +(eSplit[1] || 0);
  return len > 0 ? len : 0;
}

// src/numberStripPrecision.ts
function stripPrecision(num, precision = 15) {
  return +parseFloat(Number(num).toPrecision(precision));
}

// src/numberFloat2FixedPrecision.ts
function float2FixedPrecision(num) {
  if (num.toString().indexOf("e") === -1) {
    return Number(num.toString().replace(".", ""));
  }
  const dLen = digitLengthPrecision(num);
  const powDLen = 10 ** dLen;
  return dLen > 0 ? stripPrecision(Number(num) * powDLen) : Number(num);
}

// src/numberTimesPrecision.ts
var timesPrecision = createOperationPrecision((num1, num2) => {
  const num1Changed = float2FixedPrecision(num1);
  const num2Changed = float2FixedPrecision(num2);
  const baseNum = digitLengthPrecision(num1) + digitLengthPrecision(num2);
  const leftValue = num1Changed * num2Changed;
  checkBoundaryPrecision(leftValue);
  const baseNumPow = 10 ** baseNum;
  return leftValue / baseNumPow;
});

// src/numberDivinePrecision.ts
var dividePrecision = createOperationPrecision((num1, num2) => {
  const num1Changed = float2FixedPrecision(num1);
  const num2Changed = float2FixedPrecision(num2);
  checkBoundaryPrecision(num1Changed);
  checkBoundaryPrecision(num2Changed);
  return timesPrecision(
    num1Changed / num2Changed,
    stripPrecision(10 ** (digitLengthPrecision(num2) - digitLengthPrecision(num1)))
  );
});

// src/numberRoundPrecision.ts
function roundPrecision(num, decimal) {
  const base = 10 ** decimal;
  let result = dividePrecision(Math.round(Math.abs(timesPrecision(num, base))), base);
  if (isNumber(num) && num < 0 && result !== 0) {
    result = timesPrecision(result, -1);
  }
  return result;
}

exports.roundPrecision = roundPrecision;