forked from babel/babel
-
Notifications
You must be signed in to change notification settings - Fork 0
/
evaluation.js
149 lines (134 loc) · 4.97 KB
/
evaluation.js
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
const traverse = require("../lib").default;
const assert = require("assert");
const parse = require("babylon").parse;
function getPath(code) {
const ast = parse(code);
let path;
traverse(ast, {
Program: function (_path) {
path = _path;
_path.stop();
},
});
return path;
}
describe("evaluation", function () {
describe("evaluateTruthy", function () {
it("it should work with null", function () {
assert.strictEqual(
getPath("false || a.length === 0;").get("body")[0].evaluateTruthy(),
undefined
);
});
it("it should not mistake lack of confidence for falsy", function () {
assert.strictEqual(
getPath("foo || 'bar'").get("body")[0].evaluate().value,
undefined
);
});
});
it("should bail out on recursive evaluation", function () {
assert.strictEqual(
getPath("function fn(a) { var g = a ? 1 : 2, a = g * this.foo; }")
.get("body.0.body.body.0.declarations.1.init").evaluate().confident,
false
);
});
it("should work with repeated, indeterminate identifiers", function () {
assert.strictEqual(
getPath("var num = foo(); (num > 0 && num < 100);").get("body")[1].evaluateTruthy(),
undefined
);
});
it("should work with repeated, determinate identifiers", function () {
assert.strictEqual(
getPath("var num = 5; (num > 0 && num < 100);").get("body")[1].evaluateTruthy(),
true
);
});
it("should deopt when var is redeclared in the same scope", function () {
assert.strictEqual(
getPath("var x = 2; var y = x + 2; { var x = 3 }")
.get("body.1.declarations.0.init").evaluate().confident,
false
);
});
it("should evaluate template literals", function () {
assert.strictEqual(
getPath("var x = 8; var y = 1; var z = `value is ${x >>> y}`")
.get("body.2.declarations.0.init").evaluate().value,
"value is 4"
);
});
it("should evaluate member expressions", function () {
assert.strictEqual(
getPath("var x = 'foo'.length")
.get("body.0.declarations.0.init").evaluate().value,
3
);
const member_expr = getPath("var x = Math.min(2,Math.max(3,4));var y = Math.random();");
const eval_member_expr = member_expr.get("body.0.declarations.0.init").evaluate();
const eval_invalid_call = member_expr.get("body.1.declarations.0.init").evaluate();
assert.strictEqual(eval_member_expr.value, 2);
assert.strictEqual(eval_invalid_call.confident, false);
});
it("it should not deopt vars in different scope", function () {
const input = "var a = 5; function x() { var a = 5; var b = a + 1; } var b = a + 2";
assert.strictEqual(
getPath(input).get("body.1.body.body.1.declarations.0.init").evaluate().value,
6
);
assert.strictEqual(
getPath(input).get("body.2.declarations.0.init").evaluate().value,
7
);
});
it("it should not deopt let/const inside blocks", function () {
assert.strictEqual(
getPath("let x = 5; { let x = 1; } let y = x + 5")
.get("body.2.declarations.0.init").evaluate().value,
10
);
const constExample = "const d = true; if (d && true || false) { const d = false; d && 5; }";
assert.strictEqual(
getPath(constExample).get("body.1.test").evaluate().value,
true
);
assert.strictEqual(
getPath(constExample).get("body.1.consequent.body.1").evaluate().value,
false
);
const test_alternate = "var y = (3 < 4)? 3 + 4: 3 + 4;";
assert.strictEqual(
getPath(test_alternate)
.get("body.0.declarations.0.init.alternate").evaluate().value,
7
);
});
it("should deopt ids that are referenced before the bindings", function () {
assert.strictEqual(
getPath("let x = y + 5; let y = 5;").get("body.0.declarations.0.init").evaluate().confident,
false
);
assert.strictEqual(
getPath("if (typeof x === 'undefined') var x = {}")
.get("body.0.test").evaluate().confident,
false
);
});
it("should evaluate undefined, NaN and Infinity", () => {
assert.strictEqual(getPath("undefined").get("body.0.expression").evaluate().confident, true);
assert.strictEqual(getPath("NaN").get("body.0.expression").evaluate().confident, true);
assert.strictEqual(getPath("Infinity").get("body.0.expression").evaluate().confident, true);
});
it("should deopt redefined primitives - undefined, NaN and Infinity", () => {
const eval_undef = getPath("let undefined; undefined;").get("body.1.expression").evaluate();
const eval_nan = getPath("let NaN; NaN;").get("body.1.expression").evaluate();
const eval_inf = getPath("let Infinity; Infinity;").get("body.1.expression").evaluate();
assert.strictEqual(eval_undef.confident, false);
assert.strictEqual(eval_nan.confident, false);
assert.strictEqual(eval_inf.confident, false);
assert.strictEqual(eval_undef.deopt.type, "VariableDeclarator");
assert.strictEqual(eval_undef.deopt.parentPath.node.kind, "let");
});
});