简化版本比较逻辑

Question

有标准的npm semver版本比较库，但我在这里有一些简单的逻辑来比较semver版本：

const versionA = '14.8.3';
const versionB = '15.1.1';
const versionC = '15.1.2';

const semver = require('semver');
const assert = require('assert');

const isGreater = (a, b) => {

  const [majorA, minorA, patchA] = String(a).split('.').map(v => Number.parseInt(v));
  const [majorB, minorB, patchB] = String(b).split('.').map(v => Number.parseInt(v));


  if (majorA > majorB) {
    return true;
  }

  if (majorB > minorA) {
    return false;
  }

  if (minorA > minorB) {
    return true;
  }

  if (minorB > minorA) {
    return false;
  }

  if (patchA > patchB) {
    return true;
  }

  if (patchB > patchA) {
    return false;
  }

  return false;

};


assert(isGreater(versionB, versionA), 'version b should be greater.');
assert(isGreater(versionA, versionB), 'version b should be greater.');

我的问题是-有没有一种方法可以简化greaterThan函数中的逻辑？此函数用于复制semver.gt()中的逻辑。

Answer 1

您可以使用带有numeric选项的localeCompare (对于numeric，比较结果是"1“< "2”< "10")，这正是您要查找的逻辑：

​

const versionA = '14.8.3';
const versionB = '15.1.1';
const versionC = '15.1.2';
const versionD = '15.1.10';
const versionE = '15.2.1';
const versionF = '15.11.1';

const isGreater = (a, b) => {
  return a.localeCompare(b, undefined, { numeric: true }) === 1;
};

// first argument version comes later than second argument:
console.log(isGreater(versionB, versionA));
console.log(isGreater(versionC, versionB));
console.log(isGreater(versionD, versionC));
console.log(isGreater(versionE, versionD));
console.log(isGreater(versionF, versionE));

console.log('---');

// second comes before first:
console.log(isGreater(versionA, versionB));

// same, return value should be false:
console.log(isGreater(versionA, versionA));

​

或者，等效地，您可以传递区域设置字符串

en-US-u-kn-true

作为第二个参数，而不是{ numeric: true }。

Answer 2

我相信这在逻辑上是相同的，而且更短，但它的简单性并不完全令人惊讶

const isGreater = (a, b) => {

  const [majorA, minorA, patchA] = String(a).split('.').map(v => Number.parseInt(v));
  const [majorB, minorB, patchB] = String(b).split('.').map(v => Number.parseInt(v));

  if (majorA !== majorB) {
    return majorA > majorB;
  }

  if (minorA !== minorB) {
    return minorA > minorB;
  }

  return patchA > patchB;

};