-
-
Notifications
You must be signed in to change notification settings - Fork 2.6k
/
PatternVisitor.ts
141 lines (121 loc) · 4.04 KB
/
PatternVisitor.ts
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
import {
TSESTree,
AST_NODE_TYPES,
} from '@typescript-eslint/experimental-utils';
import { VisitorBase, VisitorOptions } from './Visitor';
type PatternVisitorCallback = (
pattern: TSESTree.Identifier,
info: {
assignments: (TSESTree.AssignmentPattern | TSESTree.AssignmentExpression)[];
rest: boolean;
topLevel: boolean;
},
) => void;
type PatternVisitorOptions = VisitorOptions;
class PatternVisitor extends VisitorBase {
public static isPattern(
node: TSESTree.Node,
): node is
| TSESTree.Identifier
| TSESTree.ObjectPattern
| TSESTree.ArrayPattern
| TSESTree.SpreadElement
| TSESTree.RestElement
| TSESTree.AssignmentPattern {
const nodeType = node.type;
return (
nodeType === AST_NODE_TYPES.Identifier ||
nodeType === AST_NODE_TYPES.ObjectPattern ||
nodeType === AST_NODE_TYPES.ArrayPattern ||
nodeType === AST_NODE_TYPES.SpreadElement ||
nodeType === AST_NODE_TYPES.RestElement ||
nodeType === AST_NODE_TYPES.AssignmentPattern
);
}
public readonly rootPattern: TSESTree.Node;
public readonly callback: PatternVisitorCallback;
public readonly assignments: (
| TSESTree.AssignmentPattern
| TSESTree.AssignmentExpression
)[] = [];
public readonly rightHandNodes: TSESTree.Node[] = [];
public readonly restElements: TSESTree.RestElement[] = [];
constructor(
options: PatternVisitorOptions,
rootPattern: TSESTree.Node,
callback: PatternVisitorCallback,
) {
super(null, options);
this.rootPattern = rootPattern;
this.callback = callback;
}
protected ArrayExpression(node: TSESTree.ArrayExpression): void {
node.elements.forEach(this.visit, this);
}
protected ArrayPattern(pattern: TSESTree.ArrayPattern): void {
for (const element of pattern.elements) {
this.visit(element);
}
}
protected AssignmentExpression(node: TSESTree.AssignmentExpression): void {
this.assignments.push(node);
this.visit(node.left);
this.rightHandNodes.push(node.right);
this.assignments.pop();
}
protected AssignmentPattern(pattern: TSESTree.AssignmentPattern): void {
this.assignments.push(pattern);
this.visit(pattern.left);
this.rightHandNodes.push(pattern.right);
this.assignments.pop();
}
protected CallExpression(node: TSESTree.CallExpression): void {
// arguments are right hand nodes.
node.arguments.forEach(a => {
this.rightHandNodes.push(a);
});
this.visit(node.callee);
}
protected Identifier(pattern: TSESTree.Identifier): void {
const lastRestElement =
this.restElements[this.restElements.length - 1] ?? null;
this.callback(pattern, {
topLevel: pattern === this.rootPattern,
rest:
lastRestElement !== null &&
lastRestElement !== undefined &&
lastRestElement.argument === pattern,
assignments: this.assignments,
});
}
protected MemberExpression(node: TSESTree.MemberExpression): void {
// Computed property's key is a right hand node.
if (node.computed) {
this.rightHandNodes.push(node.property);
}
// the object is only read, write to its property.
this.rightHandNodes.push(node.object);
}
protected Property(property: TSESTree.Property): void {
// Computed property's key is a right hand node.
if (property.computed) {
this.rightHandNodes.push(property.key);
}
// If it's shorthand, its key is same as its value.
// If it's shorthand and has its default value, its key is same as its value.left (the value is AssignmentPattern).
// If it's not shorthand, the name of new variable is its value's.
this.visit(property.value);
}
protected RestElement(pattern: TSESTree.RestElement): void {
this.restElements.push(pattern);
this.visit(pattern.argument);
this.restElements.pop();
}
protected SpreadElement(node: TSESTree.SpreadElement): void {
this.visit(node.argument);
}
protected TSTypeAnnotation(): void {
// we don't want to visit types
}
}
export { PatternVisitor, PatternVisitorCallback, PatternVisitorOptions };