Javascript 用来自 Array 的子字符串替换字符串

Question

I am wondering how to replace in string substring that is stored in array of substrings and do it the best way. I was reading about RegEx and String.replace() method but can't find working example. The goal is to remove from company name the substring such as ".ltd" or "ltd"

My code:

 function removeCompanySubstring(string) { var regex = companySubstrings console.log(regex) return string.replace(regex, ""); } console.log(removeCompanySubstring("Company.ltd"))

companySubstrings.json

"companySubstrings": [
        "ltd.",
        ".ltd",
        "GmbH",
        ...
    ],

When I call the function removeCompanySubstring("Company GmbH") the output is wrong and it returns

> Company GmbH

But the outpt should be

> Company

and it should remove the "Gmbh" from Company

Answer 1

You can't pass an array as regex. You have to loop over. See the snippet.

 var companySubstrings = [ "ltd.", ".ltd", "GmbH", ]; function removeCompanySubstring(string) { for (var needle of companySubstrings) { string = string.replace(needle, ""); } return string.trim(); } console.log(removeCompanySubstring("Company GmbH.ltd"))

Answer 2

Watch out for edge-cases!

In terms of implementation, you can:

• build your regex as @Teemu said (without forgetting to escape the . character which is a substitute for any character in the regex world)
• or loop over the array and replace any occurrence of the substrings

No matter what method you choose, you should finally trim the string to remove any trailing/leading whitespace left.

Although it's far from being bulletproof methods: consider what happens if you change lowercase to uppercase? Sure you can make it case insensitive using a regex, but then what if the pattern is also found within the actual name of the company?

For instance "limited" which you listed as a possible substring can be found in a company name like "Unlimited clothing limited". The french "SAS" could be found in "SASUN GmbH"...

And this gets worse the longer companySubstrings gets because you'll be more and more likely to find one of the patterns within a legit company name as you keep adding new patterns.

Also, should the substring be found multiple time in a company name, should we replace just a single occurrence? Then which one: first, last? Another one? Same question for when we find different substrings in the same company name.

Turns out it's not such a trivial problem at all.

Two different implementations, with their own shortcomings

 var companySubstrings = [ "SAS", "limited", "ltd.", ".ltd", "GmbH" ]; // Using a regex to replace all occurrences (case insensitive) function removeCompanySubstringRegex(string) { // If the companySubstrings are never changing, you should declare // the regex as a const outside of this function so you don't // build a new regex each time you call it return string.replace( new RegExp( companySubstrings.join('|').replaceAll('.', '\\.'), 'gi' // g: replace all - i: case insensitive ), '' ).trim(); } // Looping over the substrings array to replace matches (case sensitive) function removeCompanySubstringLoop(string) { let result = string; companySubstrings.forEach( // use `result.replaceAll(str, '')` to replace **all** occurrences // and get the same behavior as the `g` flag in a regex str => result = result.replace(str, '') ); return result.trim(); } // Loop: `SAS Company.ltd` -> `Company` ✅ console.log( 'Loop: ', removeCompanySubstringLoop("SAS Company.ltd") ); // Regex: `SAS Company.ltd` -> `Company` ✅ console.log( 'Regex: ', removeCompanySubstringRegex("SAS Company.ltd") ) // Loop: `Unlimited limited` -> `Un limited`  console.log( 'Tricky name (loop): ', removeCompanySubstringLoop("Unlimited limited") ) // Regex: `Unlimited limited` -> `Un`  console.log( 'Tricky name (regex): ', removeCompanySubstringRegex("Unlimited limited") )

Answer 3

I made a case insensitive version:)

 let companySubstrings = [ "SAS", "ltd.", ".ltd", "GmbH", ]; function removeCompanySubstring(compName) { let result = compName; companySubstrings.forEach(str => { let regex = RegExp(str, 'gi'); result = result.replace(regex, '') }); return result.trim(); } console.log(removeCompanySubstring("SAS Company.ltd")) console.log(removeCompanySubstring("Company.ltd")); console.log(removeCompanySubstring("Company GmbH")); console.log(removeCompanySubstring("LTD. Company GmbH"));

Answer 4

In the approach you want to solve, I would suggest you to just create a Regex for the Array of strings you are getting in response.

function removeCompanySubstring(string) {
  regexArr = new RegExp(companySubstrings.join("|"), 'gi'); 
  return string.replace(regexArr, "");
}
 console.log(removeCompanySubstring("Company .ltd"))

ex-

 var arr = ["ltd.", ".ltd","GmbH"]; //the array you have
 var regexArr = new RegExp(arr.join("|"), 'gi'); //the regex you need

then follow the similar approach you are now using just update regex with regexArr you have created.