Looping through an array of assorted strings, I want to push into another array the strings that are separated by 3 or 4 hyphens

• addon-4-website-m2m
• addon-4-website-comp-m2m

but not strings separated by 3 or 4 hyphens ending with annual:

• addon-4-website-annual
• addon-4-website-com-annual

What is the regex for filtering them?

CodePudding user response：

It is easier to use split and endsWith than a regular expression.

let parts = str.split('-');
if (parts.length >= 4 && parts.length <= 5 && !str.endsWith('annual')) {
    // add to result
}

CodePudding user response：

I would express the regex as:

^\w (?:-\w ){2,3}-(?!annual$)\w $

This pattern says to match:

• ^ from the start of the string
• \w a leading (first) component
• (?:-\w ){2,3} followed by 2 or 3 middle components
• - followed by hyphen
• (?!annual$) assert that last component does NOT end in "annual"
• \w then match any other component
• $ end of the string

Here is a working demo.

Here is how you may use this pattern in JavaScript:

if (/^\w (?:-\w ){2,3}-(?!annual$)\w $/.test("addon-4-website-m2m")) {
    console.log("MATCH");
}

CodePudding user response：

You can use a negative lookahead:

^(\w -){3,4}(?!annual)\w $

• ^ start of the string
• (\w -){3,4} 3 or 4 words followed by an hyphen
• (?!annual) not followed by this word
• \w last word
• $ end of the string