### Install Shift Traverser

Source: https://github.com/jsoverson/shift-traverse-js/blob/master/README.md

Installs the shift-traverser package using npm.

```sh
npm install shift-traverser
```

--------------------------------

### Traverse AST Nodes

Source: https://github.com/jsoverson/shift-traverse-js/blob/master/README.md

Demonstrates how to use the `traverse` function to walk through an Abstract Syntax Tree (AST). It allows defining `enter` and `leave` callbacks for each node.

```js
import {traverse} from "shift-traverser"

traverse(tree, {
    enter(node) {
        console.log(`entering ${node.type}`);
    },

    leave(node) {
        console.log(`leaving ${node.type}`);
    }
});
```

--------------------------------

### Replace AST Nodes

Source: https://github.com/jsoverson/shift-traverse-js/blob/master/README.md

Shows how to use the `replace` function to modify an AST. It takes an AST and a visitor object, allowing nodes to be replaced by returning new nodes from the `enter` callback.

```js
import parse from 'shift-parser'
import codegen from "shift-codegen";
import { LiteralStringExpression } from "shift-ast";
import { replace, Syntax } from '../'

let code = `
function test() {
    console.log("HELLO WORLD");
}
`;
let tree = parse(code);
let transformed = replace(tree, {
    enter(node, parent) {
        if (node.type === Syntax.LiteralStringExpression) {
            return new LiteralStringExpression('ご注文はうさぎですか？');
        }
    }
});
assert(codegen(transformed) === `function test(){console.log("ご注文はうさぎですか？")}`);
```

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