feat: init

node_modules/regexp-tree/dist/optimizer/index.js

@@ -0,0 +1,91 @@
+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2017-present Dmitry Soshnikov <dmitry.soshnikov@gmail.com>
+ */
+
+'use strict';
+
+var clone = require('../utils/clone');
+var parser = require('../parser');
+var transform = require('../transform');
+var optimizationTransforms = require('./transforms');
+
+module.exports = {
+  /**
+   * Optimizer transforms a regular expression into an optimized version,
+   * replacing some sub-expressions with their idiomatic patterns.
+   *
+   * @param string | RegExp | AST - a regexp to optimize.
+   *
+   * @return TransformResult - an optimized regexp.
+   *
+   * Example:
+   *
+   *   /[a-zA-Z_0-9][a-zA-Z_0-9]*\e{1,}/
+   *
+   * Optimized to:
+   *
+   *   /\w+e+/
+   */
+  optimize: function optimize(regexp) {
+    var _ref = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {},
+        _ref$whitelist = _ref.whitelist,
+        whitelist = _ref$whitelist === undefined ? [] : _ref$whitelist,
+        _ref$blacklist = _ref.blacklist,
+        blacklist = _ref$blacklist === undefined ? [] : _ref$blacklist;
+
+    var transformsRaw = whitelist.length > 0 ? whitelist : Array.from(optimizationTransforms.keys());
+
+    var transformToApply = transformsRaw.filter(function (transform) {
+      return !blacklist.includes(transform);
+    });
+
+    var ast = regexp;
+    if (regexp instanceof RegExp) {
+      regexp = '' + regexp;
+    }
+
+    if (typeof regexp === 'string') {
+      ast = parser.parse(regexp);
+    }
+
+    var result = new transform.TransformResult(ast);
+    var prevResultString = void 0;
+
+    do {
+      // Get a copy of the current state here so
+      // we can compare it with the state at the
+      // end of the loop.
+      prevResultString = result.toString();
+      ast = clone(result.getAST());
+
+      transformToApply.forEach(function (transformName) {
+        if (!optimizationTransforms.has(transformName)) {
+          throw new Error('Unknown optimization-transform: ' + transformName + '. ' + 'Available transforms are: ' + Array.from(optimizationTransforms.keys()).join(', '));
+        }
+
+        var transformer = optimizationTransforms.get(transformName);
+
+        // Don't override result just yet since we
+        // might want to rollback the transform
+        var newResult = transform.transform(ast, transformer);
+
+        if (newResult.toString() !== result.toString()) {
+          if (newResult.toString().length <= result.toString().length) {
+            result = newResult;
+          } else {
+            // Result has changed but is not shorter:
+            // restore ast to its previous state.
+
+            ast = clone(result.getAST());
+          }
+        }
+      });
+
+      // Keep running the optimizer until it stops
+      // making any change to the regexp.
+    } while (result.toString() !== prevResultString);
+
+    return result;
+  }
+};