javascript - 不使用 Regex 而是循环搜索和替换字符串，如何一次替换多个单词？

Question

我找到了一种在不使用 Regex 的情况下进行字符串搜索和替换的方法，但是当我想替换多个实例时，它会一次执行一个，而不是同时执行所有实例。我怎样才能让循环工作？

'use strict'

function main() {
  document.addEventListener('DOMContentLoaded', function() {
    document.getElementById('replace').addEventListener('click', replace);
    document.getElementById('replaceAll').addEventListener('click', replaceAll);
  });

}

function replace(evnt) {
  evnt.preventDefault()
  let userText = document.getElementById('input').value;
  let search = document.getElementById('search').value;
  let replaceText = document.getElementById('replaceText').value;
  let caseSensitive = document.getElementById('case').checked;
  document.getElementById('input').value = userText.replace(search, replaceText);

}

function replaceAll(evnt) {
  evnt.preventDefault();
  let userText = document.getElementById('input').value;
  let search = document.getElementById('search').value;
  let replaceText = document.getElementById('replaceText').value;

  for (let r = 0; r < userText.indexOf(search); r++) {
    document.getElementById('input').value = userText.replace(search, replaceText);
    console.log(r);

  }
}

<form id="form">
  <div>
    <textarea id="input" row="10" cols="50" placeholder="Enter text here"></textarea>
  </div>
  <div>
    <input type="text" id="search" name="search">
    <input type="text" id="replaceText" name="replacebox">
  </div>
  <div>
    <input type="checkbox" id="case" name="case sensitivity" />
    <label for="uppercase">case sensitivity</label>
  </div>
  <div>
    <button type="submit" id="replace">Replace</button>
  </div>
  <div>
    <button type="submit" id="replaceAll">Replace all</button>
  </div>
</form>

标签： javascriptreplacereplaceall

Answer 1

在

for(let r = 0; r < userText.indexOf(search);r++) {
    document.getElementById('input').value = userText.replace(search, replaceText);
}

在每次迭代中，您都会获取userText字符串并替换其中的一个子字符串。您没有从先前的迭代中获取替换的字符串；您正在使用原始字符串，因此最后最多只能进行一次替换。

重新分配一个变量，也许userText，然后在循环完成后分配给输入：

for(let r = 0; r < userText.indexOf(search);r++) {
    userText = userText.replace(search, replaceText);
}
document.getElementById('input').value = userText;

也可以使用.includes，更直观：

while (userText.includes(search)) {
  userText = userText.replace(search, replaceText);
}

'use strict'

function main() {
  document.addEventListener('DOMContentLoaded', function() {
    document.getElementById('replace').addEventListener('click', replace);
    document.getElementById('replaceAll').addEventListener('click', replaceAll);
  });

}

function replace(evnt) {
  evnt.preventDefault()
  let userText = document.getElementById('input').value;
  let search = document.getElementById('search').value;
  let replaceText = document.getElementById('replaceText').value;
  let caseSensitive = document.getElementById('case').checked;
  document.getElementById('input').value = userText.replace(search, replaceText);

}

function replaceAll(evnt) {
  evnt.preventDefault();
  let userText = document.getElementById('input').value;
  let replaceText = document.getElementById('replaceText').value;
  while (userText.includes(search.value)) {
    userText = userText.replace(search.value, replaceText);
  }
  input.value = userText;
}
const [repButton, repAllButton] = document.querySelectorAll('button');
repButton.onclick = replace;
repAllButton.onclick = replaceAll;

<form id="form">
  <div>
    <textarea id="input" row="10" cols="50" placeholder="Enter text here">abcabc</textarea>
  </div>
  <div>
    <input type="text" id="search" name="search" value="abc">
    <input type="text" id="replaceText" name="replacebox" value="123">
  </div>
  <div>
    <input type="checkbox" id="case" name="case sensitivity" />
    <label for="uppercase">case sensitivity</label>
  </div>
  <div>
    <button type="submit" id="replace">Replace</button>
  </div>
  <div>
    <button type="submit" id="replaceAll">Replace all</button>
  </div>
</form>