const regex = /^rgba?\((?:\s+)?(?<r>\d+(?<unit>%?))(?:\s+)?(?<separator>[\s|,])(?:\s+)?(?<g>\d+\k<unit>)(?:\s+)?\k<separator>(?:\s+)?(?<b>\d+\k<unit>)(?:\s+)?(?:(?<=(?:,.+))(?:,(?:\s+)?(?<a>(?:\d+)?(?:\.?\d+)))?(?:\s+)?)?\)$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^rgba?\\((?:\\s+)?(?<r>\\d+(?<unit>%?))(?:\\s+)?(?<separator>[\\s|,])(?:\\s+)?(?<g>\\d+\\k<unit>)(?:\\s+)?\\k<separator>(?:\\s+)?(?<b>\\d+\\k<unit>)(?:\\s+)?(?:(?<=(?:,.+))(?:,(?:\\s+)?(?<a>(?:\\d+)?(?:\\.?\\d+)))?(?:\\s+)?)?\\)$', 'gm')
const str = `// Valid
rgb(120 , 42 , 55)
rgb(23%, 100%, 0%)
rgb(120 42 55)
rgb(23% 100% 0%)
rgb(0 0 0)
rgba(23, 53, 0)
// Invalid
rgb(255, 120 0)
rgb(100% 32 75)
// When an alpha channel is defined, separator must be comma (not sure why but you can try it in browser to see for yourself)
// Valid
rgb(255, 255, 255, 1)
rgb(255, 255, 255, .643)
rgb(255, 255, 255, 1.324 )
rgba(255, 255, 255, 1)
rgba(255, 255, 255, .643)
rgba(255, 255, 255, 1.324 )
// Invalid
rgb(255, 255, 255, )
rgb(255, 255, 255, .)
rgba(255 255 255 1)
rgba(255 255 255, 1)`;
// 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