I'm having a hard time testing whether a provided string (that likely starts with !) is surrounded by word boundries.
// found in Mozilla's RegExp guide.
function escapeRegExp(str) {
return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}
let msg = "a b c !test1 d e f";
let cmd = "!test1";
let re = new RegExp("\\b" + escapeRegExp(cmd) + "\\b");
console.log(`re: ${re.test(msg)}`); // re: false
I assume this behaviour occurs, because punctuation itself is counted as a word boundry?
At least escaping the punctuation seems not to solve the problem. (I've tested a modified version of escapeRegExp() that includes !, same result.)
As an workaround I've used a version that splits msg at the white space and compares the elements with cmd. I'm not very happy with this solution as it breaks when cmd itself includes whitespace.
You can use adaptive dynamic word boundaries:
// found in Mozilla's RegExp guide.
function escapeRegExp(str) {
return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}
let msg = "a b c !test1 d e f";
let cmd = "!test1";
let re = new RegExp("(?!\\B\\w)" + escapeRegExp(cmd) + "(?<!\\w\\B)");
// console.log(re.source);// => (?!\B\w)!test1(?<!\w\B)
console.log(`re: ${re.test(msg)}`);
// => re: trueThe (?!\B\w)!test1(?<!\w\B) regex matches !test1 and
(?!\B\w) - checks if the next char is a word char, and if it is, a word boundary is required at the current location, else, the word boundary is not required(?<!\w\B) - checks if the previous char is a word char, and if it is, a word boundary is required at the current location, else, the word boundary is not required.See some more details about adaptive dynamic word boundaries in my YT video.