Improve code quality and write tests

node_modules/regexp-tree/dist/compat-transpiler/transforms/compat-dotall-s-transform.js

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+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+/**
+ * A regexp-tree plugin to translate `/./s` to `/[\0-\uFFFF]/`.
+ */
+
+module.exports = {
+
+  // Whether `u` flag present. In which case we transform to
+  // \u{10FFFF} instead of \uFFFF.
+  _hasUFlag: false,
+
+  // Only run this plugin if we have `s` flag.
+  shouldRun: function shouldRun(ast) {
+    var shouldRun = ast.flags.includes('s');
+
+    if (!shouldRun) {
+      return false;
+    }
+
+    // Strip the `s` flag.
+    ast.flags = ast.flags.replace('s', '');
+
+    // Whether we have also `u`.
+    this._hasUFlag = ast.flags.includes('u');
+
+    return true;
+  },
+  Char: function Char(path) {
+    var node = path.node;
+
+
+    if (node.kind !== 'meta' || node.value !== '.') {
+      return;
+    }
+
+    var toValue = '\\uFFFF';
+    var toSymbol = '\uFFFF';
+
+    if (this._hasUFlag) {
+      toValue = '\\u{10FFFF}';
+      toSymbol = '\uDBFF\uDFFF';
+    }
+
+    path.replace({
+      type: 'CharacterClass',
+      expressions: [{
+        type: 'ClassRange',
+        from: {
+          type: 'Char',
+          value: '\\0',
+          kind: 'decimal',
+          symbol: '\0'
+        },
+        to: {
+          type: 'Char',
+          value: toValue,
+          kind: 'unicode',
+          symbol: toSymbol
+        }
+      }]
+    });
+  }
+};

node_modules/regexp-tree/dist/compat-transpiler/transforms/compat-named-capturing-groups-transform.js

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+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+/**
+ * A regexp-tree plugin to translate `/(?<name>a)\k<name>/` to `/(a)\1/`.
+ */
+
+module.exports = {
+  // To track the names of the groups, and return them
+  // in the transform result state.
+  //
+  // A map from name to number: {foo: 2, bar: 4}
+  _groupNames: {},
+
+  /**
+   * Initialises the trasnform.
+   */
+  init: function init() {
+    this._groupNames = {};
+  },
+
+
+  /**
+   * Returns extra state, which eventually is returned to
+   */
+  getExtra: function getExtra() {
+    return this._groupNames;
+  },
+  Group: function Group(path) {
+    var node = path.node;
+
+
+    if (!node.name) {
+      return;
+    }
+
+    // Record group name.
+    this._groupNames[node.name] = node.number;
+
+    delete node.name;
+    delete node.nameRaw;
+  },
+  Backreference: function Backreference(path) {
+    var node = path.node;
+
+
+    if (node.kind !== 'name') {
+      return;
+    }
+
+    node.kind = 'number';
+    node.reference = node.number;
+    delete node.referenceRaw;
+  }
+};

node_modules/regexp-tree/dist/compat-transpiler/transforms/compat-x-flag-transform.js

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+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+/**
+ * A regexp-tree plugin to remove `x` flag `/foo/x` to `/foo/`.
+ *
+ * Note: other features of `x` flags (whitespace, comments) are
+ * already removed at parsing stage.
+ */
+
+module.exports = {
+  RegExp: function RegExp(_ref) {
+    var node = _ref.node;
+
+    if (node.flags.includes('x')) {
+      node.flags = node.flags.replace('x', '');
+    }
+  }
+};

node_modules/regexp-tree/dist/compat-transpiler/transforms/index.js

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+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+module.exports = {
+  // "dotAll" `s` flag
+  dotAll: require('./compat-dotall-s-transform'),
+
+  // Named capturing groups.
+  namedCapturingGroups: require('./compat-named-capturing-groups-transform'),
+
+  // `x` flag
+  xFlag: require('./compat-x-flag-transform')
+};