readme.md

Hook Navigator

Untangle the web of state setters in React.js

If you've developed in React, you've probably spent time investigating multiple re-renders. This tool analyzes your React component and identifies state variables that trigger multiple setter calls for other state variables.

Example

Suppose you have a React component:

...

const [a, setA] = useState("");
const [b, setB] = useState("");
const [c, setC] = useState("");

useEffect(() => {
  setB(a + a);
}, [a]);

useEffect(() => {
  setC(a + b);
}, [a, b]);

...

A change in a will trigger b to change, and a change in a or b will trigger c to change. So when a changes, setC will be called twice:

Schematically, we have the following "call paths" between setters:

 setA
  |  \
  |   \
  |    \
  |     \
  |      \
  |       \
  |        |
  V        V
setB ---> setC

You can see the two call paths between a's and c's setters.

Running this tool on this example outputs:

Analyzing  ./example/ExampleComponent.js :


These state variable trigger ONE setter for these state variables:
        - Setting a triggers setting b via the chain [ 'a', 'b' ]
        - Setting b triggers setting c via the chain [ 'b', 'c' ]

Good job :)


These state variable trigger MULTIPLE setters for these state variables:
        - Setting a triggers setting c via the chains:
                -  [ 'a', 'b', 'c' ]
                -  [ 'a', 'c' ]

Please address these.

Node versions

Works in Node 14.

Install

Install dependencies with npm install

Test

Tests use jest. Run npm test.

To use

1. install globally using npm i -g
2. or don't

If you install globally, run with hook-navigator --files {list of react components you want to test separated by spaces}

If you don't install globally, run with node index.js --files {list of react components you want to test separated by spaces}