JavaScript計算字符串實際長度詳情 - javascript,string,長度點墨博客

計算字符串的實際長度,雙字節字符(包括漢字在內)長度計2,ASCII字符計1

方法1:使用match:

export function getByteLenMatch(data) {
  let result = 0;
  for (let s of data) {
    result += s.match(/[^\\x00-\\xff]/ig) == null ? 1 : 2;
  }
  return result;
}

方法2:使用replace:

export function getByteLenReplace(data) {
  return data.replace(/[^\\x00-\\xff]/ig, "aa").length;
}

測試代碼:

    let testData = new Array(50000000).fill("哈").toString();
    for (let i = 0; i < 3; i++) {
      console.time("getByteLenMatch");
      getByteLenMatch(testData);
      console.timeEnd("getByteLenMatch");
      console.time("getByteLenReplace");
      getByteLenReplace(testData);
      console.timeEnd("getByteLenReplace");
    }

性能比較(單位ms):

字符串長度	match	replace
50,000,000	8051	8626
50,000,000	9351	8019
50,000,000	10384	7512
10,000,000	1631	1783
10,000,000	1646	1343
10,000,000	1663	1372
5,000,000	799	728
5,000,000	822	806
5,000,000	884	645
1,000,000	165	128
1,000,000	166	143
1,000,000	170	113
500,000	84	58
500,000	83	54
500,000	86	61
100,000	20	7
100,000	18	5
100,000	20	5
50,000	11.79	3.01
50,000	10.39	2.68
50,000	11.99	2.82
10,000	4.13	0.60
10,000	4.32	0.59
10,000	5.48	0.58
5,000	1.88	0.31
5,000	1.36	0.33
5,000	2.71	0.31
1,000	1.67	0.07
1,000	0.21	0.07
1,000	1.02	0.06
500	0.0840	0.0322
500	0.0820	0.0332
500	0.0840	0.0320
100	0.0229	0.0100
100	0.0432	0.0149
100	0.0471	0.0161