/
transformExpression.ts
360 lines (342 loc) 路 12.1 KB
/
transformExpression.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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
// - Parse expressions in templates into compound expressions so that each
// identifier gets more accurate source-map locations.
//
// - Prefix identifiers with `_ctx.` or `$xxx` (for known binding types) so that
// they are accessed from the right source
//
// - This transform is only applied in non-browser builds because it relies on
// an additional JavaScript parser. In the browser, there is no source-map
// support and the code is wrapped in `with (this) { ... }`.
import { NodeTransform, TransformContext } from '../transform'
import {
NodeTypes,
createSimpleExpression,
ExpressionNode,
SimpleExpressionNode,
CompoundExpressionNode,
createCompoundExpression,
ConstantTypes
} from '../ast'
import {
isInDestructureAssignment,
isStaticProperty,
isStaticPropertyKey,
walkIdentifiers
} from '../babelUtils'
import { advancePositionWithClone, isSimpleIdentifier } from '../utils'
import {
isGloballyWhitelisted,
makeMap,
babelParserDefaultPlugins,
hasOwn,
isString
} from '@vue/shared'
import { createCompilerError, ErrorCodes } from '../errors'
import {
Node,
Identifier,
AssignmentExpression,
UpdateExpression
} from '@babel/types'
import { validateBrowserExpression } from '../validateExpression'
import { parse } from '@babel/parser'
import { IS_REF, UNREF } from '../runtimeHelpers'
import { BindingTypes } from '../options'
const isLiteralWhitelisted = /*#__PURE__*/ makeMap('true,false,null,this')
export const transformExpression: NodeTransform = (node, context) => {
if (node.type === NodeTypes.INTERPOLATION) {
node.content = processExpression(
node.content as SimpleExpressionNode,
context
)
} else if (node.type === NodeTypes.ELEMENT) {
// handle directives on element
for (let i = 0; i < node.props.length; i++) {
const dir = node.props[i]
// do not process for v-on & v-for since they are special handled
if (dir.type === NodeTypes.DIRECTIVE && dir.name !== 'for') {
const exp = dir.exp
const arg = dir.arg
// do not process exp if this is v-on:arg - we need special handling
// for wrapping inline statements.
if (
exp &&
exp.type === NodeTypes.SIMPLE_EXPRESSION &&
!(dir.name === 'on' && arg)
) {
dir.exp = processExpression(
exp,
context,
// slot args must be processed as function params
dir.name === 'slot'
)
}
if (arg && arg.type === NodeTypes.SIMPLE_EXPRESSION && !arg.isStatic) {
dir.arg = processExpression(arg, context)
}
}
}
}
}
interface PrefixMeta {
prefix?: string
isConstant: boolean
start: number
end: number
scopeIds?: Set<string>
}
// Important: since this function uses Node.js only dependencies, it should
// always be used with a leading !__BROWSER__ check so that it can be
// tree-shaken from the browser build.
export function processExpression(
node: SimpleExpressionNode,
context: TransformContext,
// some expressions like v-slot props & v-for aliases should be parsed as
// function params
asParams = false,
// v-on handler values may contain multiple statements
asRawStatements = false
): ExpressionNode {
if (__BROWSER__) {
if (__DEV__) {
// simple in-browser validation (same logic in 2.x)
validateBrowserExpression(node, context, asParams, asRawStatements)
}
return node
}
if (!context.prefixIdentifiers || !node.content.trim()) {
return node
}
const { inline, bindingMetadata } = context
const rewriteIdentifier = (raw: string, parent?: Node, id?: Identifier) => {
const type = hasOwn(bindingMetadata, raw) && bindingMetadata[raw]
if (inline) {
// x = y
const isAssignmentLVal =
parent && parent.type === 'AssignmentExpression' && parent.left === id
// x++
const isUpdateArg =
parent && parent.type === 'UpdateExpression' && parent.argument === id
// ({ x } = y)
const isDestructureAssignment =
parent && isInDestructureAssignment(parent, parentStack)
if (type === BindingTypes.SETUP_CONST) {
return raw
} else if (type === BindingTypes.SETUP_REF) {
return `${raw}.value`
} else if (type === BindingTypes.SETUP_MAYBE_REF) {
// const binding that may or may not be ref
// if it's not a ref, then assignments don't make sense -
// so we ignore the non-ref assignment case and generate code
// that assumes the value to be a ref for more efficiency
return isAssignmentLVal || isUpdateArg || isDestructureAssignment
? `${raw}.value`
: `${context.helperString(UNREF)}(${raw})`
} else if (type === BindingTypes.SETUP_LET) {
if (isAssignmentLVal) {
// let binding.
// this is a bit more tricky as we need to cover the case where
// let is a local non-ref value, and we need to replicate the
// right hand side value.
// x = y --> isRef(x) ? x.value = y : x = y
const { right: rVal, operator } = parent as AssignmentExpression
const rExp = rawExp.slice(rVal.start! - 1, rVal.end! - 1)
const rExpString = stringifyExpression(
processExpression(createSimpleExpression(rExp, false), context)
)
return `${context.helperString(IS_REF)}(${raw})${
context.isTS ? ` //@ts-ignore\n` : ``
} ? ${raw}.value ${operator} ${rExpString} : ${raw}`
} else if (isUpdateArg) {
// make id replace parent in the code range so the raw update operator
// is removed
id!.start = parent!.start
id!.end = parent!.end
const { prefix: isPrefix, operator } = parent as UpdateExpression
const prefix = isPrefix ? operator : ``
const postfix = isPrefix ? `` : operator
// let binding.
// x++ --> isRef(a) ? a.value++ : a++
return `${context.helperString(IS_REF)}(${raw})${
context.isTS ? ` //@ts-ignore\n` : ``
} ? ${prefix}${raw}.value${postfix} : ${prefix}${raw}${postfix}`
} else if (isDestructureAssignment) {
// TODO
// let binding in a destructure assignment - it's very tricky to
// handle both possible cases here without altering the original
// structure of the code, so we just assume it's not a ref here
// for now
return raw
} else {
return `${context.helperString(UNREF)}(${raw})`
}
} else if (type === BindingTypes.PROPS) {
// use __props which is generated by compileScript so in ts mode
// it gets correct type
return `__props.${raw}`
}
} else {
if (type && type.startsWith('setup')) {
// setup bindings in non-inline mode
return `$setup.${raw}`
} else if (type) {
return `$${type}.${raw}`
}
}
// fallback to ctx
return `_ctx.${raw}`
}
// fast path if expression is a simple identifier.
const rawExp = node.content
// bail constant on parens (function invocation) and dot (member access)
const bailConstant = rawExp.indexOf(`(`) > -1 || rawExp.indexOf('.') > 0
if (isSimpleIdentifier(rawExp)) {
const isScopeVarReference = context.identifiers[rawExp]
const isAllowedGlobal = isGloballyWhitelisted(rawExp)
const isLiteral = isLiteralWhitelisted(rawExp)
if (!asParams && !isScopeVarReference && !isAllowedGlobal && !isLiteral) {
// const bindings exposed from setup can be skipped for patching but
// cannot be hoisted to module scope
if (bindingMetadata[node.content] === BindingTypes.SETUP_CONST) {
node.constType = ConstantTypes.CAN_SKIP_PATCH
}
node.content = rewriteIdentifier(rawExp)
} else if (!isScopeVarReference) {
if (isLiteral) {
node.constType = ConstantTypes.CAN_STRINGIFY
} else {
node.constType = ConstantTypes.CAN_HOIST
}
}
return node
}
let ast: any
// exp needs to be parsed differently:
// 1. Multiple inline statements (v-on, with presence of `;`): parse as raw
// exp, but make sure to pad with spaces for consistent ranges
// 2. Expressions: wrap with parens (for e.g. object expressions)
// 3. Function arguments (v-for, v-slot): place in a function argument position
const source = asRawStatements
? ` ${rawExp} `
: `(${rawExp})${asParams ? `=>{}` : ``}`
try {
ast = parse(source, {
plugins: [...context.expressionPlugins, ...babelParserDefaultPlugins]
}).program
} catch (e) {
context.onError(
createCompilerError(
ErrorCodes.X_INVALID_EXPRESSION,
node.loc,
undefined,
e.message
)
)
return node
}
type QualifiedId = Identifier & PrefixMeta
const ids: QualifiedId[] = []
const parentStack: Node[] = []
const knownIds: Record<string, number> = Object.create(context.identifiers)
walkIdentifiers(
ast,
(node, parent, _, isReferenced, isLocal) => {
if (isStaticPropertyKey(node, parent!)) {
return
}
// v2 wrapped filter call
if (__COMPAT__ && node.name.startsWith('_filter_')) {
return
}
const needPrefix = isReferenced && canPrefix(node)
if (needPrefix && !isLocal) {
if (isStaticProperty(parent!) && parent.shorthand) {
// property shorthand like { foo }, we need to add the key since
// we rewrite the value
;(node as QualifiedId).prefix = `${node.name}: `
}
node.name = rewriteIdentifier(node.name, parent, node)
ids.push(node as QualifiedId)
} else {
// The identifier is considered constant unless it's pointing to a
// local scope variable (a v-for alias, or a v-slot prop)
if (!(needPrefix && isLocal) && !bailConstant) {
;(node as QualifiedId).isConstant = true
}
// also generate sub-expressions for other identifiers for better
// source map support. (except for property keys which are static)
ids.push(node as QualifiedId)
}
},
undefined,
true, // invoke on ALL identifiers
true, // isLocal scope analysis
parentStack,
knownIds
)
// We break up the compound expression into an array of strings and sub
// expressions (for identifiers that have been prefixed). In codegen, if
// an ExpressionNode has the `.children` property, it will be used instead of
// `.content`.
const children: CompoundExpressionNode['children'] = []
ids.sort((a, b) => a.start - b.start)
ids.forEach((id, i) => {
// range is offset by -1 due to the wrapping parens when parsed
const start = id.start - 1
const end = id.end - 1
const last = ids[i - 1]
const leadingText = rawExp.slice(last ? last.end - 1 : 0, start)
if (leadingText.length || id.prefix) {
children.push(leadingText + (id.prefix || ``))
}
const source = rawExp.slice(start, end)
children.push(
createSimpleExpression(
id.name,
false,
{
source,
start: advancePositionWithClone(node.loc.start, source, start),
end: advancePositionWithClone(node.loc.start, source, end)
},
id.isConstant ? ConstantTypes.CAN_STRINGIFY : ConstantTypes.NOT_CONSTANT
)
)
if (i === ids.length - 1 && end < rawExp.length) {
children.push(rawExp.slice(end))
}
})
let ret
if (children.length) {
ret = createCompoundExpression(children, node.loc)
} else {
ret = node
ret.constType = bailConstant
? ConstantTypes.NOT_CONSTANT
: ConstantTypes.CAN_STRINGIFY
}
ret.identifiers = Object.keys(knownIds)
return ret
}
function canPrefix(id: Identifier) {
// skip whitelisted globals
if (isGloballyWhitelisted(id.name)) {
return false
}
// special case for webpack compilation
if (id.name === 'require') {
return false
}
return true
}
function stringifyExpression(exp: ExpressionNode | string): string {
if (isString(exp)) {
return exp
} else if (exp.type === NodeTypes.SIMPLE_EXPRESSION) {
return exp.content
} else {
return (exp.children as (ExpressionNode | string)[])
.map(stringifyExpression)
.join('')
}
}