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
|
/*
Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
"use strict";
/* eslint-disable no-undefined */
const Syntax = require("estraverse").Syntax;
const esrecurse = require("esrecurse");
/**
* Get last array element
* @param {array} xs - array
* @returns {any} Last elment
*/
function getLast(xs) {
return xs[xs.length - 1] || null;
}
class PatternVisitor extends esrecurse.Visitor {
static isPattern(node) {
const nodeType = node.type;
return (
nodeType === Syntax.Identifier ||
nodeType === Syntax.ObjectPattern ||
nodeType === Syntax.ArrayPattern ||
nodeType === Syntax.SpreadElement ||
nodeType === Syntax.RestElement ||
nodeType === Syntax.AssignmentPattern
);
}
constructor(options, rootPattern, callback) {
super(null, options);
this.rootPattern = rootPattern;
this.callback = callback;
this.assignments = [];
this.rightHandNodes = [];
this.restElements = [];
}
Identifier(pattern) {
const lastRestElement = getLast(this.restElements);
this.callback(pattern, {
topLevel: pattern === this.rootPattern,
rest: lastRestElement !== null && lastRestElement !== undefined && lastRestElement.argument === pattern,
assignments: this.assignments
});
}
Property(property) {
// 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);
}
ArrayPattern(pattern) {
for (let i = 0, iz = pattern.elements.length; i < iz; ++i) {
const element = pattern.elements[i];
this.visit(element);
}
}
AssignmentPattern(pattern) {
this.assignments.push(pattern);
this.visit(pattern.left);
this.rightHandNodes.push(pattern.right);
this.assignments.pop();
}
RestElement(pattern) {
this.restElements.push(pattern);
this.visit(pattern.argument);
this.restElements.pop();
}
MemberExpression(node) {
// 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);
}
//
// ForInStatement.left and AssignmentExpression.left are LeftHandSideExpression.
// By spec, LeftHandSideExpression is Pattern or MemberExpression.
// (see also: https://github.com/estree/estree/pull/20#issuecomment-74584758)
// But espree 2.0 parses to ArrayExpression, ObjectExpression, etc...
//
SpreadElement(node) {
this.visit(node.argument);
}
ArrayExpression(node) {
node.elements.forEach(this.visit, this);
}
AssignmentExpression(node) {
this.assignments.push(node);
this.visit(node.left);
this.rightHandNodes.push(node.right);
this.assignments.pop();
}
CallExpression(node) {
// arguments are right hand nodes.
node.arguments.forEach(a => {
this.rightHandNodes.push(a);
});
this.visit(node.callee);
}
}
module.exports = PatternVisitor;
/* vim: set sw=4 ts=4 et tw=80 : */
|
