diff --git a/.eslintrc.js b/.eslintrc.js
index f5287f112dd4118753be29261a1020fe80681185..60a973486da137fe5b25d826bcf6942044c47bce 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,3 +1,7 @@
 module.exports = {
-  'extends': 'airbnb'
+  'extends': 'airbnb',
+  'rules': {
+    'no-plusplus': 'off',
+    'no-mixed-operators': 'off',
+  }
 };
\ No newline at end of file
diff --git a/bin/temporary_action.js b/bin/temporary_action.js
index fea63c802a7f871cb089d13e041a04d0bf4e7b8d..4c11ffa04921386f696f99c7e82fff416fbaf1fd 100644
--- a/bin/temporary_action.js
+++ b/bin/temporary_action.js
@@ -9,7 +9,18 @@ for (const category of categories) {
     if (algorithm.startsWith('.')) continue;
     const filepath = path.resolve(__dirname, '..', 'algorithm', category, algorithm, 'code.js');
     const code = fs.readFileSync(filepath, 'utf-8');
-    const newCode = code.replace(/([a-z])_([a-z])/g, (m, m1, m2) => m1 + m2.toUpperCase());
+    const tracers = [
+      'Array1DTracer',
+      'Array2DTracer',
+      'ChartTracer',
+      'GraphTracer',
+      'LogTracer',
+      'Randomize',
+      'Tracer',
+    ];
+    const used = tracers.filter(tracer => code.includes(tracer));
+    const importLine = `import { ${used.join(', ')} } from 'algorithm-visualizer';\n\n`;
+    const newCode = importLine + code;
     fs.writeFileSync(filepath, newCode, 'utf-8');
   }
 }
\ No newline at end of file
diff --git a/src/frontend/core/datas/GraphData.js b/src/frontend/core/datas/GraphData.js
index 435e78dd919de3f1ca8e9dd89cd0fcf64cb30abc..2a1fa4f4e528fe11bc46af98cb135faddcd44c7b 100644
--- a/src/frontend/core/datas/GraphData.js
+++ b/src/frontend/core/datas/GraphData.js
@@ -1,4 +1,5 @@
 import { Data } from '/core/datas';
+import { GraphTracer } from '/core/tracers';
 import { distance } from '/common/util';
 import { tracerManager } from '/core';
 
@@ -25,7 +26,7 @@ class GraphData extends Data {
     this.logData = null;
   }
 
-  set(array2d = [], layout = GraphData.LAYOUT.CIRCLE, root = 0) {
+  set(array2d = [], layout = GraphTracer.LAYOUT.CIRCLE, root = 0) {
     const { directed, weighted } = this.options;
     const { baseWidth, baseHeight, padding } = this.dimensions;
     this.graph = new Graph([], [], directed);
@@ -53,16 +54,16 @@ class GraphData extends Data {
     const height = bottom - top;
     const rect = { left, top, right, bottom, width, height };
     switch (layout) {
-      case GraphData.LAYOUT.CIRCLE:
+      case GraphTracer.LAYOUT.CIRCLE:
         this.graph.layoutCircle(rect);
         break;
-      case GraphData.LAYOUT.TREE:
+      case GraphTracer.LAYOUT.TREE:
         this.graph.layoutTree(rect, root);
         break;
-      case GraphData.LAYOUT.RANDOM:
+      case GraphTracer.LAYOUT.RANDOM:
         this.graph.layoutRandom(rect);
         break;
-      case GraphData.LAYOUT.NONE:
+      case GraphTracer.LAYOUT.NONE:
       default:
         break;
     }
@@ -209,12 +210,4 @@ class Graph {
   }
 }
 
-GraphData.LAYOUT = {
-  CIRCLE: 'circle',
-  TREE: 'tree',
-  RANDOM: 'random',
-  NONE: 'none',
-  // FORCE_DIRECTED: 'force_directed',
-};
-
 export default GraphData;
\ No newline at end of file
diff --git a/src/frontend/core/tracerManager.jsx b/src/frontend/core/tracerManager.jsx
index 7d7e7e2ccddd24cc552270334bc5875b68479fce..767ca53ef3517f7433cdd5ba657de8cbe068f6e3 100644
--- a/src/frontend/core/tracerManager.jsx
+++ b/src/frontend/core/tracerManager.jsx
@@ -2,13 +2,17 @@ import React from 'react';
 import { Randomize, Seed } from '/core';
 import * as Tracers from '/core/tracers';
 import { Tracer } from '/core/tracers';
-import * as Datas from '/core/datas';
 import { Array1DData, Array2DData, ChartData, Data, GraphData, LogData } from '/core/datas';
 import { Array1DRenderer, Array2DRenderer, ChartRenderer, GraphRenderer, LogRenderer, Renderer } from '/core/renderers';
 
-Object.assign(window, Tracers);
-Object.assign(window, Datas);
-Object.assign(window, { Randomize });
+Object.assign(window, {
+  modules: {
+    'algorithm-visualizer': {
+      ...Tracers,
+      Randomize,
+    },
+  }
+});
 
 class TracerManager {
   constructor() {
@@ -162,12 +166,18 @@ class TracerManager {
     }
   }
 
+  sandboxEval(code){
+    const require = moduleName => window.modules[moduleName]; // fake require
+    eval(code);
+  }
+
   execute(callback) {
     try {
       const lines = this.code.split('\n').map((line, i) => line.replace(/(.+\. *wait *)(\( *\))/g, `$1(${i})`));
       const seed = new Seed();
       Tracer.seed = seed;
-      eval(Babel.transform(lines.join('\n'), { presets: ['es2015'] }).code);
+      const { code } = Babel.transform(lines.join('\n'), { presets: ['es2015'] });
+      this.sandboxEval(code);
       this.reset(seed);
       if (callback) callback();
     } catch (error) {
diff --git a/src/frontend/core/tracers/GraphTracer.js b/src/frontend/core/tracers/GraphTracer.js
index 200147cfd6c71188774764b1fd40e3614fc69037..feda89223aee6a4ae48eabfe34cdf59bc1cfd96c 100644
--- a/src/frontend/core/tracers/GraphTracer.js
+++ b/src/frontend/core/tracers/GraphTracer.js
@@ -12,4 +12,12 @@ class GraphTracer extends Tracer {
   }
 }
 
+GraphTracer.LAYOUT = {
+  CIRCLE: 'circle',
+  TREE: 'tree',
+  RANDOM: 'random',
+  NONE: 'none',
+  // FORCE_DIRECTED: 'force_directed',
+};
+
 export default GraphTracer;
\ No newline at end of file