Infinite loop detection via AST transformation

infinite-loop-detection.js

export default function (babel) {
  const { types: t } = babel;

  const infiniteLoopDetector = babel.parse(`
	function __infiniteLoopDetector() {

		loopdetector.count += 1;

		if(loopdetector.count > 10000) {
			throw new Error("Infinte loop detected.")
		}
	}

	function __infiniteLoopDetector__reset() {
		loopdetector.count = 0;
	}

`);

  //Todo: Need diff approch;
  let isGlobalFNsAreAdded = false;

  function injectDetectorIntoLoop(path) {
    const detectorFn = babel.parse(`
		/** Injected loop detector*/
		__infiniteLoopDetector()
	`);

    const resetFn = babel.parse(`
	/** Reset Counter before loop start*/
	__infiniteLoopDetector__reset()
	`);
    path.node.body.body.unshift(detectorFn);
    const thisIndex = path.parent.body.findIndex((e) => e === path.node);
    path.parent.body.splice(thisIndex, 0, resetFn);
  }

  return {
    name: "ast-transform", // not required
    visitor: {
      Program(path) {
        if (isGlobalFNsAreAdded) return;
        path.node.body.unshift(infiniteLoopDetector);
        isGlobalFNsAreAdded = true;
      },

      ForStatement(path) {
        injectDetectorIntoLoop(path);
      },
      WhileStatement(path) {
        injectDetectorIntoLoop(path);
      }
    }
  };
}

DEMO: https://astexplorer.net/#/gist/61b6f2e1bd64913c5a3502b80fbb571b/5ec1f4ccf90aba38cb4bdb6acf0d4d5969cce2ce

Input: file1.js

const x = 10;

while(true) {
  console.log("Hey")
  console.log("hi")
}


x = 10;
x = 10;
x = 10;


for(;;) {
  console.log("Hey")
  console.log("hi")
}

---

Output: file1.transpiled.js

function __infiniteLoopDetector() {
  loopdetector.count += 1;

  if (loopdetector.count > 10000) {
    throw new Error("Infinte loop detected.");
  }
}

function __infiniteLoopDetector__reset() {
  loopdetector.count = 0;
}

const x = 10;

/** Reset Counter before loop start*/
__infiniteLoopDetector__reset();

while (true) {
  /** Injected loop detector*/
  __infiniteLoopDetector();

  console.log("Hey");
  console.log("hi");
}

x = 10;
x = 10;
x = 10;

/** Reset Counter before loop start*/
__infiniteLoopDetector__reset();

for (;;) {
  /** Injected loop detector*/
  __infiniteLoopDetector();

  console.log("Hey");
  console.log("hi");
}