const regex = new RegExp('^(?:\\t| )*(?:#|%|;|//|--|REM|C|!) (?:#{64} (.*)|#{32} (.*)|#{16} (.*)|#{8} (.*)|#{4} (.*)|#{2} (.*))$', 'mg')
const str = `Valid comments that start with "#":
# ################################################################ First Level
# ################################ Second Level
# ################ Third level
# ######## Fourth Level
# #### Fifth level
# ## Sixth level
Valid comments that start with different characters:
// ################################################################ 1st Level
; ################################ 2nd Level
REM ################ 3rd level
C ######## 4th Level
% #### 5th level
-- ## 6th level
Valid comments that start with spaces or tabs:
# ################################################################ 1st level
; ################################ 2nd Level
Invalid comments:
################################################################ No initial character
; ################################################ Hashes not a power of 2
@ ################ Character not recognized
C ########No space after hashes
% %%%%%%%% No hashes
. # #### Period before spaces
;#### No space after character`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions