flow like the river

VISUALIZACION/node_modules/safer-eval/lib/common.js

@@ -0,0 +1,140 @@
+'use strict';
+
+var clones = require('clones');
+
+var hasWindow = typeof window !== 'undefined';
+exports.hasWindow = hasWindow;
+var hasGlobal = typeof global !== 'undefined';
+exports.hasGlobal = hasGlobal;
+var FN_NOOP = 'function () {}';
+var NON_IDENTIFIER = /^\d|-|^(break|case|catch|continue|debugger|default|delete|do|else|finally|for|function|if|in|instanceof|new|return|switch|this|throw|try|typeof|var|void|while|with|class|const|enum|export|extends|import|super|implements|interface|let|package|private|protected|public|static|yield|null|true|false)$/;
+
+var isIdentifier = function isIdentifier(key) {
+  return !NON_IDENTIFIER.test(key);
+};
+
+exports.isIdentifier = isIdentifier;
+/**
+* create a fresh context where nearly nothing is allowed
+* @private
+*/
+
+exports.createContext = function () {
+  // protection might not be complete!
+  var context = {
+    // disallowed
+    global: undefined,
+    process: undefined,
+    module: undefined,
+    require: undefined,
+    document: undefined,
+    window: undefined,
+    Window: undefined,
+    // no evil...
+    eval: undefined,
+    Function: undefined
+  };
+
+  var fillContext = function fillContext(root) {
+    Object.keys(root).forEach(function (key) {
+      if (isIdentifier(key)) {
+        context[key] = undefined;
+      }
+    });
+  }; // locally define all potential global vars
+
+
+  if (hasGlobal) {
+    fillContext(global);
+    cloneFunctions(context);
+    context.Buffer = _protect('Buffer');
+    context.console = clones(console, console); // console needs special treatment
+
+    context.console.constructor.constructor = FN_NOOP;
+  }
+
+  if (hasWindow) {
+    fillContext(window, true);
+    cloneFunctions(context);
+    protectBuiltInObjects(context);
+    context.console = clones(console, console); // console needs special treatment
+
+    try {
+      context.Object.constructor.constructor = FN_NOOP;
+    } catch (e) {}
+  }
+
+  return context;
+};
+/**
+* Apply allowed context properties
+* @private
+*/
+
+
+exports.allow = function (context, newContext) {
+  Object.keys(context || {}).forEach(function (key) {
+    if (isIdentifier(key)) {
+      newContext[key] = context[key]; // this is harmful - objects can be overwritten
+    }
+  });
+};
+/**
+* clone global functions
+* @private
+*/
+
+
+function cloneFunctions(context) {
+  ;
+  ['clearImmediate', 'clearInterval', 'clearTimeout'].forEach(function (str) {
+    try {
+      var fn = new Function("return ".concat(str))(); // eslint-disable-line no-new-func
+
+      context[str] = fn ? function () {
+        return fn.apply(null, [].slice.call(arguments));
+      } : undefined;
+    } catch (e) {}
+  });
+  ['setImmediate', 'setInterval', 'setTimeout'].forEach(function (str) {
+    try {
+      var fn = new Function("return ".concat(str))(); // eslint-disable-line no-new-func
+
+      context[str] = fn ? function (f) {
+        if (typeof f === 'function') {
+          return fn.apply(null, [].slice.call(arguments));
+        } else {
+          throw new Error(str + ' requires function as argument');
+        }
+      } : undefined;
+    } catch (e) {}
+  });
+}
+/**
+* wraps up build-in objects using a cloned copy
+* protect object against overwriting
+* @private
+*/
+
+
+function protectBuiltInObjects(context) {
+  ;
+  ['Object', 'Boolean', 'Symbol', 'Error', 'EvalError', 'InternalError', 'RangeError', 'ReferenceError', 'SyntaxError', 'TypeError', 'URIError', 'Number', 'Math', 'Date', 'String', 'RegExp', 'Array', 'Int8Array', 'Uint8Array', 'Uint8ClampedArray', 'Int16Array', 'Uint16Array', 'Int32Array', 'Uint32Array', 'Float32Array', 'Float64Array', 'Map', 'Set', 'WeakMap', 'WeakSet', 'ArrayBuffer', 'SharedArrayBuffer', 'Atomics', 'DataView', 'JSON', 'Promise', 'Generator', 'GeneratorFunction', 'Reflect', 'Proxy', 'Intl', 'Buffer'].forEach(function (str) {
+    try {
+      context[str] = _protect(str);
+      new context[str](); // eslint-disable-line no-new
+    } catch (e) {}
+  });
+}
+/**
+* @private
+*/
+
+
+function _protect(str) {
+  try {
+    var type = new Function("return ".concat(str))(); // eslint-disable-line no-new-func
+
+    return type ? clones.classes(type) : undefined;
+  } catch (e) {}
+}