blob: a34a23aeceff3527d60fce42cc606ab97405a569 [file] [log] [blame]
// @flow strict
/**
* An ES6 string tag that fixes indentation. Also removes leading newlines
* and trailing spaces and tabs, but keeps trailing newlines.
*
* Example usage:
* const str = dedent`
* {
* test
* }
* `;
* str === "{\n test\n}\n";
*/
export default function dedent(
strings: $ReadOnlyArray<string>,
...values: $ReadOnlyArray<string>
): string {
let str = '';
for (let i = 0; i < strings.length; ++i) {
str += strings[i];
if (i < values.length) {
/* istanbul ignore next (ignore else inside Babel generated code) */
const value = values[i];
str += value; // interpolation
}
}
const trimmedStr = str
.replace(/^\n*/m, '') // remove leading newline
.replace(/[ \t]*$/, ''); // remove trailing spaces and tabs
// fixes indentation by removing leading spaces and tabs from each line
let indent = '';
for (const char of trimmedStr) {
if (char !== ' ' && char !== '\t') {
break;
}
indent += char;
}
return trimmedStr.replace(RegExp('^' + indent, 'mg'), ''); // remove indent
}