const regex = /^(-?((0|[1-9]+)\.\d{1,4}|[1-9])|0)$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^(-?((0|[1-9]+)\\.\\d{1,4}|[1-9])|0)$', 'gm')
const str = `Acceptable:
0
0.1
0.12
0.123
0.1234
1
1.1
...
123456789.1234
-0.1
-0.12
-0.123
-0.1234
-1
-1.1
...
-123456789.1234
No
-123456789.123456789
-
+
-0
0123456789.1234
007
+0.1
+123456789.1234
.1234
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