feat: add sandboxed eval function

Author: k3nsei

index.js

@@ -0,0 +1,30 @@
+(function (factory) {
+    if (typeof module === "object" && typeof module.exports === "object") {
+        var v = factory(require, exports);
+        if (v !== undefined) module.exports = v;
+    }
+    else if (typeof define === "function" && define.amd) {
+        define(["require", "exports"], factory);
+    }
+})(function (require, exports) {
+    "use strict";
+    Object.defineProperty(exports, "__esModule", { value: true });
+    const proxyCache = new WeakMap();
+    exports.compile = (expression) => {
+        const fn = new Function('scope', `with (scope) { return ${expression}; }`);
+        return (scope) => {
+            if (!proxyCache.has(scope)) {
+                proxyCache.set(scope, new Proxy(scope, {
+                    has: () => true,
+                    get: (target, key) => {
+                        if (key === Symbol.unscopables || typeof key !== 'string') {
+                            return undefined;
+                        }
+                        return target[key];
+                    }
+                }));
+            }
+            return fn(proxyCache.get(scope));
+        };
+    };
+});

index.ts

@@ -0,0 +1,27 @@
+interface Scope {
+    [key: string]: any;
+}
+
+const proxyCache: WeakMap<Scope, any> = new WeakMap();
+
+export const compile = (expression: string): (scope: Scope) => any => {
+    const fn = new Function('scope', `with (scope) { return ${expression}; }`);
+
+    return (scope: Scope): any => {
+        if (!proxyCache.has(scope)) {
+            proxyCache.set(
+                scope,
+                new Proxy(scope, {
+                    has: () => true,
+                    get: (target: Scope, key: unknown) => {
+                        if (key === Symbol.unscopables || typeof key !== 'string') {
+                            return undefined;
+                        }
+                        return target[key as string];
+                    }
+                })
+            );
+        }
+        return fn(proxyCache.get(scope));
+    };
+};

tsconfig.json

@@ -0,0 +1,8 @@
+{
+  "compilerOptions": {
+    "target": "ES2015",
+    "module": "umd",
+    "strict": true,
+    "lib": ["es2015"]
+  }
+}