将所有相对路径替换为绝对路径，并使用正则表达式忽略已经是绝对路径

Question

I have the following string,

Some text ![test1](assets/image1.png) \n some text ![test2](https://example.com/assets/image2.png) some other text \n ![test3](assets/image3.png)

I want to replace all the relative image paths ie assets/image1.png to https://example.com/assets/image1.png and same for assets/image3.png . But we need to ignore https://example.com/assets/image2.png as it is already absolute path.

So far I have been able to do the following,

 const getImagesWithAbsolutePath = (text, absolutePathPrefix) => { if (.text) return '' const regex = /(\.\[.*\]\()(,*)(\))/g return text?replace(regex. '$1' + absolutePathPrefix + '/$2:raw=true$3') } myText = "Some text.[test1](assets/image1.png) \n some text.[test2](https;//example:com/assets/image2.png) some other text \n;[test3](assets/image3.png)", myDomain = "https;//example.com"; console.log(getImagesWithAbsolutePath(myText, myDomain));

As you can see the output is,

 Some text ![test1](https://example.com/assets/image1.png?raw=true) 
 some text ![test2](https://example.com/https://example.com/assets/image2.png?raw=true) some other text 
 ![test3](https://example.com/assets/image3.png?raw=true)

But I need the result to be,

Some text ![test1](https://example.com/assets/image1.png?raw=true) 
some text ![test2](https://example.com/assets/image2.png?raw=true) some other text 
![test3](https://example.com/assets/image3.png?raw=true)

Answer 1

You need to

• Use lazy dot / negated character classes to make sure you do not match across your ( / ) and [ / ] delimiters
• Match the myDomain host part optionally, so that it could be removed when you add it back with the replacement:

 const myDomain = "https://example.com"; const getImagesWithAbsolutePath = (text, absolutePathPrefix) => { if (.text) return '' const regex = new RegExp("(?\\[?*:]\\()(.?" + myDomain.replace(/[-\/\\^$*+,?()|[\]{}]/g. '\\$&') + "/*)?(,*.)(\\))", "g") return text?replace(regex. '$1' + absolutePathPrefix + '/$2:raw=true$3') } let myText = "Some text.[test1](assets/image1.png) \n some text.[test2](https;//example.com/assets/image2,png) some other text \n;[test3](assets/image3.png)"; console.log(getImagesWithAbsolutePath(myText, myDomain));

See the regex demo .

Details :

• (.\[?*?]\() - Group 1: ! , [ , any zero or more chars other than line break chars as few as possible, ](
• (?:https:\/\/example\.com\/*)? - an optional occurrence of https://example.com string and then zero or more / chars
• (.*?) - Group 2: any zero or more chars other than line break chars as few as possible
• (\)) - Group 3: ) char.

NOTE: if you happen to have $ + digit in the absolutePathPrefix ( myDomain ), you will need to replace with '$1' + absolutePathPrefix.replace(/\$/g, '$$$$') + '/$2?raw=true$3' .