CODEWITHSUNDEEP
javascriptregexreplace
Hejhejhej123
Hejhejhej123

Reputation: 1195

Replace text but not if contain specific characters?

In JavaScript, I am using the below code to replace text that matches a certain string. The replacement wraps the string like this: "A(hello)". It works great but if there are two strings that are the same, for example: "Hello hi Hello", only the first one will get marked and if I am trying twice, it will get marked double, like this: "A(A(Hello)) Hi Hello".

A solution to this could be to not replace a word if it contains "A(" or is between "A(" and ")"; both would work.

Any idea how it can be achieved?

Note: I cant use replaceAll because if there is already a word that is replaced and a new word is added, then the first one will be overwritten. Therefore I need a solution like above. For example,If I have a string saying "Hello hi", and I mark Hello, it will say "A(Hello) hi", but if I then add Hello again to the text and replace it, it will look like this: A(A(Hello)) hi A(Hello).

Here is what I got so far:

let text = "Hello hi Hello!"
let selection = "Hello"
let A = `A(${selection})`
let addWoman = text.replace(selection, A)

Upvotes: 2

Views: 1027

Answers (2)

Wiktor Stribiżew
Wiktor Stribiżew

Reputation: 626738

A solution to this could be to not replace a word if it contains "A(" or is between "A(" and ")"; both would work.

To avoid re-matching selection inside a A(...) string, you can match A(...) and capture it into a group so as to know if the group matched, it should be kept, else, match the word of your choice:

let text = "Hello hi Hello!"
let selection = "Hello"
let A = `A(${selection})`
const rx = new RegExp(String.raw`(A\([^()]*\))|${selection.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&')}`, 'g')
let addWoman = text.replace(rx, (x,y) =>  y || A)
console.log(addWoman);
// Replacing the second time does not modify the string:
console.log(addWoman.replace(rx, (x,y) =>  y || A))

The regex will look like /(A\([^()]*\))|Hello/g, it matches

  • (A\([^()]*\)) - Group 1: A and then ( followed with zero or more chars other than ( and ) and then a ) char
  • | - or
  • Hello - a Hello string.

Upvotes: 1

anubhava
anubhava

Reputation: 784998

You can use a negative lookahead assertion in your pattern that fails the match if we A( before full word Hello:

(?<!A\()\bHello\b

And replace it with A($&)

RegEx Demo

Code:

let text = "Hello hi Hello!";
let selection = "Hello";
let A = `A(${selection})`;
let re = new RegExp(`(?<!A\\()\\b${selection}\\b`, "g");
let addWoman = text.replace(re, A);

console.log(addWoman);

console.log(addWoman.replace(re, A));

Upvotes: 3

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