stylelint/src/utils/matchesStringOrRegExp.js

Modern CSS linter

/**
 * Compares a string to a second value that, if it fits a certain convention,
 * is converted to a regular expression before the comparison.
 * If it doesn't fit the convention, then two strings are compared.
 *
 * Any strings starting and ending with `/` are interpreted
 * as regular expressions.
 *
 * @param {string|array} input
 * @param {string|regexp|array} comparison
 * @return {boolean|object} `false` if no match is found.
 *   If a match is found, returns an object with these properties:
 *   - `match`: the `input` value that had a match
 *   - `pattern`: the `comparison` pattern that had a match
 */
export default function matchesStringOrRegExp(input, comparison) {
  if (!Array.isArray(input)) {
    return testAgainstStringOrArray(input, comparison)
  }

  for (const inputItem of input) {
    const testResult = testAgainstStringOrArray(inputItem, comparison)
    if (testResult) {
      return testResult
    }
  }

  return false
}

function testAgainstStringOrArray(value, comparison) {
  if (!Array.isArray(comparison)) {
    return testAgainstString(value, comparison)
  }

  for (const comparisonItem of comparison) {
    const testResult = testAgainstString(value, comparisonItem)
    if (testResult) {
      return testResult
    }
  }
  return false
}

function testAgainstString(value, comparison) {
  const comparisonIsRegex = comparison[0] === "/"
    && comparison[comparison.length - 1] === "/"

  if (comparisonIsRegex) {
    const valueMatches = new RegExp(comparison.slice(1, -1)).test(value)
    return (valueMatches)
      ? { match: value, pattern: comparison }
      : false
  }

  return (value === comparison)
    ? { match: value, pattern: comparison }
    : false
}