generateHookMap.js — react Source File

Source Code

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

import {getHookNamesMappingFromAST} from './astUtils';
import {encode, decode} from '@jridgewell/sourcemap-codec';

// Missing types in @babel/types
type File = any;

export type HookMap = {
  names: $ReadOnlyArray<string>,
  mappings: HookMapMappings,
};

export type EncodedHookMap = {
  names: $ReadOnlyArray<string>,
  mappings: string,
};

// See generateHookMap below for more details on formatting
export type HookMapEntry = [
  number, // 1-indexed line number
  number, // 0-indexed column number
  number, // 0-indexed index into names array
  number, // TODO: filler number to support reusing encoding from `sourcemap-codec` (see TODO below)
];
export type HookMapLine = HookMapEntry[];
export type HookMapMappings = HookMapLine[];

/**
 * Given a parsed source code AST, returns a "Hook Map", which is a
 * mapping which maps locations in the source code to their to their
 * corresponding Hook name, if there is a relevant Hook name for that
 * location (see getHookNamesMappingFromAST for details on the
 * representation of the mapping).
 *
 * The format of the Hook Map follows a similar format as the `name`
 * and `mappings` fields in the Source Map spec, where `names` is an
 * array of strings, and `mappings` contains segments lines, columns,
 * and indices into the `names` array.
 *
 * E.g.:
 *   {
 *     names: ["<no-hook>", "state"],
 *     mappings: [
 *       [ -> line 1
 *         [1, 0, 0],  -> line, col, name index
 *       ],
 *       [ -> line 2
 *         [2, 5, 1],  -> line, col, name index
 *         [2, 15, 0],  -> line, col, name index
 *       ],
 *     ],
 *   }
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