Jscodeshift's scope methods

jscodeshift-scope-methods.js

// getScope() is a method provided by jscodeshift that can be used to get the Scope object for a given Node. 
// A Scope object represents the lexical scope of a node in the abstract syntax tree (AST). 
// It contains information about the variables, functions, and other declarations that are in scope at a given point in the code.

// Here's an example of how getScope() can be used:

import { getScope } from 'jscodeshift';

const source = `
  function foo() {
    let x = 10;
    console.log(x);
  }
`;

const ast = parse(source);

// Get the scope for the function body
const scope = getScope(ast.program.body[0].body);

console.log(scope.variables); // [{ name: 'x' }]


// getBindings() is another method provided by jscodeshift that can be used to get the bindings (i.e., variables, functions, etc.) 
// in a given Scope. It returns an object with keys for each binding type (e.g., variables, functions, etc.) and values that are arrays of binding names.

// Here's an example of how getBindings() can be used:

import { getScope, getBindings } from 'jscodeshift';

const source = `
  function foo() {
    let x = 10;
    console.log(x);
  }
`;

const ast = parse(source);

// Get the scope for the function body
const scope = getScope(ast.program.body[0].body);

console.log(getBindings(scope));
/*
{
  variables: ['x']
}
*/



// withScope() is a method provided by jscodeshift that allows you to execute a callback function with a given Scope object as the current scope.
// This can be useful when you want to perform operations within the context of a specific scope.

// Here's an example of how withScope() can be used:

import { withScope } from 'jscodeshift';

const source = `
  function foo() {
    let x = 10;
    console.log(x);
  }
`;

const ast = parse(source);

// Get the scope for the function body
const scope = getScope(ast.program.body[0].body);

withScope(scope, () => {
  // Within this callback function, the current scope is set to `scope`
  console.log(getCurrentScope().variables); // [{ name: 'x' }]
});



// Here are some additional examples of using getScope(), getBindings(), and withScope() from jscodeshift:

import { getScope, getBindings, withScope } from 'jscodeshift';

// Example 1: Getting the scope for a function declaration
const source = `
  function foo() {
    let x = 10;
    console.log(x);
  }
`;

const ast = parse(source);

// Get the scope for the function declaration
const scope = getScope(ast.program.body[0]);

console.log(scope.variables); // [{ name: 'x' }]

// Example 2: Getting the bindings for a block statement
const source = `
  {
    let x = 10;
    let y = 20;
    const z = 30;
    function foo() {}
  }
`;

const ast = parse(source);

// Get the scope for the block statement
const scope = getScope(ast.program.body[0]);

console.log(getBindings(scope));
/*
{
  variables: ['x', 'y'],
  functions: ['foo']
}
*/

// Example 3: Using withScope to execute a callback function with a specific scope
const source = `
  function foo() {
    let x = 10;
    console.log(x);
  }
`;

const ast = parse(source);

// Get the scope for the function declaration
const scope = getScope(ast.program.body[0]);

withScope(scope, () => {
  console.log(getCurrentScope().variables); // [{ name: 'x' }]
});