This code generates errors and I want to replace only first 3 over 4 match

https://jsfiddle.net/9Lfj0dva/

let test = ". . . .";
const regex = /\./gm;
let matchAll = test.matchAll(regex);
console.log(Array.from(matchAll).length);
const replacements = [1, 2, 3];
test = test.replace(regex, () => replacements.next().value);
console.log(test);

CodePudding user response：

Something like this:

let test = ". . . .";
const regex = /\./m;
const replacements = [1, 2, 3];
replacements.forEach((replacement) => test = test.replace(regex, replacement));
console.log(test);

<iframe name="sif1" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

I remove the global flag from the regular expression to only replace the first match found, and then loop through the replacements array.

CodePudding user response：

1) You can initialize the couter to 0 and then replace it with replacement array data until index < length - 1

let test = ". . . .";
const regex = /\./gm;
let matchAll = [...test.matchAll(regex)];

const replacements = [1, 2, 3];
let index = 0;
const length = matchAll.length;

const result = test.replace(regex, (match) => index < length - 1 ? replacements[index  ] : match );
console.log(result);

<iframe name="sif2" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>

2) If you want to generalise it then you can add one more condition index < replacements.length

let test = ". . . . . .";
const regex = /\./gm;
let matchAll = [...test.matchAll(regex)];
const length = matchAll.length;
const replacements = [1, 2, 3];
let index = 0;
const result = test.replace(regex, (match) =>
  index < length - 1 && index < replacements.length
    ? replacements[index  ]
    : match
);
console.log(result);

<iframe name="sif3" sandbox="allow-forms allow-modals allow-scripts" frameborder="0"></iframe>