如果你换个方式工作可能会更好。循环遍历Map，并替换在Map中与项目匹配的文本中找到的整个单词：

const standardizeMap = new Map([
  ['Hello world', 'How are you'],
  ['apple pen', 'appleP'],
  ['Swaziland', 'Eswatini'],
])

let text1 = 'Hello world I have an apple pen in Swaziland'
let text2 = 'Hello world I have an apple penin Swaziland'

function replaceText(text, map) {
  for (let [key, value] of map) {
    let re = new RegExp(`\\b${key}\\b`, 'g')
    text = text.replace(re, value)
  }

  return text
}

console.log(replaceText(text1, standardizeMap))
console.log(replaceText(text2, standardizeMap))

调用String.replace(/\w+/g, (word) => doStuff())（或replaceAll，same thing except that replaceAll requires the 'g' flag）将让该方法对\w+的每个匹配序列执行替换。您可以使用控制台日志记录来查看它们：

>> let text = "Hello world I have an apple pen in Swaziland";
>> text.replace(/\w+/g, function(word) {console.log(word);return word});
Hello
world
I
have
an
apple
pen
in
Swaziland

所以，你应该遍历你的map，对于每个条目，在文本中将所有出现的键替换为它的值。
相反，您应该循环遍历您的map，并且对于每个条目，在文本中将条目的键的所有出现替换为它的值，例如如下所示。

let text = "Hello world I have an apple pen in Swaziland" ;
for (const [key, value] of standardizeMap) {
    text = text.replaceAll(key, value);
}

您需要替换standardizeMap中的每个键值，并替换所有出现的键。

const standardizeMap = new Map([
  ["Hello world", "How are you"],
  ["apple pen", "appleP"],
  ["Swaziland", "Eswatini"],
]);

const input = "Hello world I have an apple pen in Swaziland";

function replaceString(map, input) {
  let output = input;
  for (const [key, value] of map) {
    output = output.replace(key, value);
  }
  return output;
}

console.log(replaceString(standardizeMap, input));