replace old array with new array in string

Question

I have a var contains string and I have array with words from the string called oldWords and new array with the new words called newWords I want to replace oldWords with newWords in the string I already try to do it with for loop but it return the string with only the last word replaced.

Code:

let myStr = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce sapien magna.",
 old_Words = ["Lorem", "ipsum"],
 new_Words = ["word1", "word2"];
 
for (let i = 0; i < old_Words.length; i++) {
 var newStr = myStr.replace(old_Words[i], new_Words[i]);
}
console.log(newStr);

output should be:

"word1 word2 dolor sit amet, consectetur adipiscing elit. Fusce sapien magna."

Answer 1

Start with let newStr = myStr; before the loop, then do newStr = newStr.replace(...) inside the loop:

let myStr = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce sapien magna.",
 old_Words = ["Lorem","ipsum"],
 new_Words = ["word1","word2"],
 newStr = myStr;
for (let i = 0; i < old_Words.length; i++){
 newStr = newStr.replace(old_Words[i], new_Words[i]);
}
console.log(newStr);

• Keith: Note: put Lorem again in your myStr.. It won't replace.
• Abdelrhman Mohamed: @Keith yes I want to replace it for the first time only>

Answer 2

You can replace all the occurrences of old words with new words as follows:

NOTE: This can replace multiple occurrences of words as well.

let myStr = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Lorem ipsum dolor Fusce sapien magna.",
 old_Words = ["Lorem","ipsum"],
 new_Words = ["word1","word2"];
 
old_Words.forEach((oldWord, idx) => {
 myStr = myStr.replace(RegExp(oldWord, 'g'), new_Words[idx])
});
console.log(myStr)

let myStr = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Lorem Fusce ipsum sapien magna.",
 old_Words = ["Lorem","ipsum"],
 new_Words = ["word1","word2"];
 
old_Words.forEach((oldWord, idx) => {
 myStr = myStr.replace(RegExp(oldWord, 'g'), new_Words[idx])
});
console.log(myStr)