File size: 3,474 Bytes
369fac9 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 |
import { WalkerBase } from './walker.js';
/**
* @typedef { import('estree').Node} Node
* @typedef { import('./walker.js').WalkerContext} WalkerContext
* @typedef {(
* this: WalkerContext,
* node: Node,
* parent: Node | null,
* key: string | number | symbol | null | undefined,
* index: number | null | undefined
* ) => Promise<void>} AsyncHandler
*/
export class AsyncWalker extends WalkerBase {
/**
*
* @param {AsyncHandler} [enter]
* @param {AsyncHandler} [leave]
*/
constructor(enter, leave) {
super();
/** @type {boolean} */
this.should_skip = false;
/** @type {boolean} */
this.should_remove = false;
/** @type {Node | null} */
this.replacement = null;
/** @type {WalkerContext} */
this.context = {
skip: () => (this.should_skip = true),
remove: () => (this.should_remove = true),
replace: (node) => (this.replacement = node)
};
/** @type {AsyncHandler | undefined} */
this.enter = enter;
/** @type {AsyncHandler | undefined} */
this.leave = leave;
}
/**
* @template {Node} Parent
* @param {Node} node
* @param {Parent | null} parent
* @param {keyof Parent} [prop]
* @param {number | null} [index]
* @returns {Promise<Node | null>}
*/
async visit(node, parent, prop, index) {
if (node) {
if (this.enter) {
const _should_skip = this.should_skip;
const _should_remove = this.should_remove;
const _replacement = this.replacement;
this.should_skip = false;
this.should_remove = false;
this.replacement = null;
await this.enter.call(this.context, node, parent, prop, index);
if (this.replacement) {
node = this.replacement;
this.replace(parent, prop, index, node);
}
if (this.should_remove) {
this.remove(parent, prop, index);
}
const skipped = this.should_skip;
const removed = this.should_remove;
this.should_skip = _should_skip;
this.should_remove = _should_remove;
this.replacement = _replacement;
if (skipped) return node;
if (removed) return null;
}
/** @type {keyof Node} */
let key;
for (key in node) {
/** @type {unknown} */
const value = node[key];
if (value && typeof value === 'object') {
if (Array.isArray(value)) {
const nodes = /** @type {Array<unknown>} */ (value);
for (let i = 0; i < nodes.length; i += 1) {
const item = nodes[i];
if (isNode(item)) {
if (!(await this.visit(item, node, key, i))) {
// removed
i--;
}
}
}
} else if (isNode(value)) {
await this.visit(value, node, key, null);
}
}
}
if (this.leave) {
const _replacement = this.replacement;
const _should_remove = this.should_remove;
this.replacement = null;
this.should_remove = false;
await this.leave.call(this.context, node, parent, prop, index);
if (this.replacement) {
node = this.replacement;
this.replace(parent, prop, index, node);
}
if (this.should_remove) {
this.remove(parent, prop, index);
}
const removed = this.should_remove;
this.replacement = _replacement;
this.should_remove = _should_remove;
if (removed) return null;
}
}
return node;
}
}
/**
* Ducktype a node.
*
* @param {unknown} value
* @returns {value is Node}
*/
function isNode(value) {
return (
value !== null && typeof value === 'object' && 'type' in value && typeof value.type === 'string'
);
}
|