src/optimizer/transforms/char-class-to-meta-transform.js
function rewriteNumberRanges(path) {
  const {node} = path;

  node.expressions.forEach((expression, i) => {
    if (isFullNumberRange(expression)) {
      path.getChild(i).replace({
        type: 'Char',
        value: '\\d',
        kind: 'meta',
      });
    }
  });
}
function rewriteNumberRanges(path) {
  const {node} = path;

  node.expressions.forEach((expression, i) => {
    if (isFullNumberRange(expression)) {
      path.getChild(i).replace({
        type: 'Char',
        value: '\\d',
        kind: 'meta',
      });
    }
  });
}
Rewrites number ranges: [0-9] -> \d