如何在函数本身的 JS replace() 函数中重用正则表达式的匹配值？

Question

假设我有一个字符串，我想在某个字符串中进行匹配。为了找到它，我使用正则表达式，然后替换它。但是，我如何将它替换为匹配本身但已编辑？

我很难使用 match() 和 matchAll()，因为输入文本不一定是字符串，而且匹配函数的输出在我使用的上下文中根本没有意义它在。他们 return 作为 RegExpStringIterator(s).

目的：

正在尝试制作 google 编辑页面内容的扩展程序。

例如

regex = /123/g
let text = "XYZ string is some string is a string, but 123 is what I want to change."
let edit = text.replace(regex, numGen(***not sure what to pass here***))

console.log(edit)

function numGen(match) {
//Here I want to get the match and add the string "4" to it
}

"""
Expected outcome of "console.log(edit)": 
XYZ string is some string is a string, but ***1234*** is what I want to change.
"""

Answer 1

你是这个意思吗？检查内联评论

UPD 匹配时调用外部函数

// External function to call with each match
const numGen = match => {
  // Here you get the match as argument from replace function
  // Then add the string "4" to it
  match += "4";
  // Then return final result back to replace
  return match;
}

// Replace method part
const regex = /string/g;
let counter = 0;
let text = "XYZ string is some string is a string.";

// Just set your external function as replace parameter.
// Matched string will be passed to it as arguments
let edit = text.replace(regex, numGen);

// Result
console.log(edit);

Answer 2

根据您的示例，如果您只需要将 string/s （例如文本）附加到匹配结果，您可以简单地使用 replace():

const regex = /123/g;
const text = "XYZ string is some string is a string, but 123 is what I want to change.";
const edit = text.replace(regex, '***$&***');
// $& means the whole matched string
// result: XYZ string is some string is a string, but ***123*** is what I want to change.

如果你需要运行一些代码来改变匹配结果，那么你可以使用replacerFunction:

const regex = /123/g;
const text = "XYZ string is some string is a string, but 123 is what I want to change.";
const edit = text.replace(regex, function(m) {
  // m here means the whole matched string
  // for example, let's double the number
  return m * 2;
  // resulat: XYZ string is some string is a string, but 246 is what I want to change.
});

同上但使用箭头函数：

const regex = /123/g;
const text = "XYZ string is some string is a string, but 123 is what I want to change.";
const edit = text.replace(regex, m => {
  // m here means the whole matched string
  // for example, let's double the number
  return m * 2;
  // result: XYZ string is some string is a string, but 246 is what I want to change.
});

注：对于单次操作，上面也可以写成：

const edit = text.replace(regex, m => m * 2);

如何在函数本身的 JS replace() 函数中重用正则表达式的匹配值？

How to reuse matched value of regex in JS replace() function in the function itself?

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