-
-
Notifications
You must be signed in to change notification settings - Fork 0
/
syntax.js
302 lines (266 loc) · 7.61 KB
/
syntax.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
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
/**
* @import {Extension, State, TokenizeContext, Tokenizer} from 'micromark-util-types'
* @import {Options} from 'micromark-extension-mdxjs-esm'
*/
import {ok as assert} from 'devlop'
import {blankLine} from 'micromark-core-commonmark'
import {asciiAlpha, markdownLineEnding} from 'micromark-util-character'
import {eventsToAcorn} from 'micromark-util-events-to-acorn'
import {codes, types} from 'micromark-util-symbol'
import {positionFromEstree} from 'unist-util-position-from-estree'
import {VFileMessage} from 'vfile-message'
const blankLineBefore = {tokenize: tokenizeNextBlank, partial: true}
const trouble = 'https://github.com/micromark/micromark-extension-mdxjs-esm'
const allowedAcornTypes = new Set([
'ExportAllDeclaration',
'ExportDefaultDeclaration',
'ExportNamedDeclaration',
'ImportDeclaration'
])
/**
* Create an extension for `micromark` to enable MDX ESM syntax.
*
* @param {Options} options
* Configuration (required).
* @returns {Extension}
* Extension for `micromark` that can be passed in `extensions` to enable MDX
* ESM syntax.
*/
export function mdxjsEsm(options) {
const exportImportConstruct = {tokenize: tokenizeExportImport, concrete: true}
if (!options || !options.acorn || !options.acorn.parse) {
throw new Error('Expected an `acorn` instance passed in as `options.acorn`')
}
const acorn = options.acorn
const acornOptions = Object.assign(
{ecmaVersion: 2024, sourceType: 'module'},
options.acornOptions,
{locations: true}
)
return {
flow: {
[codes.lowercaseE]: exportImportConstruct,
[codes.lowercaseI]: exportImportConstruct
}
}
/**
* @this {TokenizeContext}
* @type {Tokenizer}
*/
function tokenizeExportImport(effects, ok, nok) {
const self = this
const definedModuleSpecifiers =
self.parser.definedModuleSpecifiers ||
(self.parser.definedModuleSpecifiers = [])
const eventStart = this.events.length + 1 // Add the main `mdxjsEsm` token
let buffer = ''
return self.interrupt ? nok : start
/**
* Start of MDX ESM.
*
* ```markdown
* > | import a from 'b'
* ^
* ```
*
* @type {State}
*/
function start(code) {
assert(
code === codes.lowercaseE || code === codes.lowercaseI,
'expected `e` or `i`'
)
// Only at the start of a line, not at whitespace or in a container.
if (self.now().column > 1) return nok(code)
effects.enter('mdxjsEsm')
effects.enter('mdxjsEsmData')
effects.consume(code)
// eslint-disable-next-line unicorn/prefer-code-point
buffer += String.fromCharCode(code)
return word
}
/**
* In keyword.
*
* ```markdown
* > | import a from 'b'
* ^^^^^^
* ```
*
* @type {State}
*/
function word(code) {
if (asciiAlpha(code)) {
effects.consume(code)
// @ts-expect-error: definitely a number.
// eslint-disable-next-line unicorn/prefer-code-point
buffer += String.fromCharCode(code)
return word
}
if (
(buffer === 'import' || buffer === 'export') &&
code === codes.space
) {
effects.consume(code)
return inside
}
return nok(code)
}
/**
* In data.
*
* ```markdown
* > | import a from 'b'
* ^
* ```
*
* @type {State}
*/
function inside(code) {
if (code === codes.eof || markdownLineEnding(code)) {
effects.exit('mdxjsEsmData')
return lineStart(code)
}
effects.consume(code)
return inside
}
/**
* At line ending.
*
* ```markdown
* > | import a from 'b'
* ^
* | export {a}
* ```
*
* @type {State}
*/
function lineStart(code) {
if (code === codes.eof) {
return atEnd(code)
}
if (markdownLineEnding(code)) {
return effects.check(blankLineBefore, atEnd, continuationStart)(code)
}
effects.enter('mdxjsEsmData')
return inside(code)
}
/**
* At line ending that continues.
*
* ```markdown
* > | import a from 'b'
* ^
* | export {a}
* ```
*
* @type {State}
*/
function continuationStart(code) {
assert(markdownLineEnding(code))
effects.enter(types.lineEnding)
effects.consume(code)
effects.exit(types.lineEnding)
return lineStart
}
/**
* At end of line (blank or eof).
*
* ```markdown
* > | import a from 'b'
* ^
* ```
*
* @type {State}
*/
function atEnd(code) {
const result = eventsToAcorn(self.events.slice(eventStart), {
acorn,
acornOptions,
tokenTypes: ['mdxjsEsmData'],
prefix:
definedModuleSpecifiers.length > 0
? 'var ' + definedModuleSpecifiers.join(',') + '\n'
: ''
})
if (result.error) {
// There’s an error, which could be solved with more content, and there
// is more content.
if (code !== codes.eof && result.swallow) {
return continuationStart(code)
}
const error = new VFileMessage(
'Could not parse import/exports with acorn',
{
cause: result.error,
place: {
line: result.error.loc.line,
column: result.error.loc.column + 1,
offset: result.error.pos
},
ruleId: 'acorn',
source: 'micromark-extension-mdxjs-esm'
}
)
error.url = trouble + '#could-not-parse-importexports-with-acorn'
throw error
}
assert(result.estree, 'expected `estree` to be defined')
// Remove the `VariableDeclaration`.
if (definedModuleSpecifiers.length > 0) {
const declaration = result.estree.body.shift()
assert(declaration)
assert(declaration.type === 'VariableDeclaration')
}
let index = -1
while (++index < result.estree.body.length) {
const node = result.estree.body[index]
if (!allowedAcornTypes.has(node.type)) {
const error = new VFileMessage(
'Unexpected `' +
node.type +
'` in code: only import/exports are supported',
{
place: positionFromEstree(node),
ruleId: 'non-esm',
source: 'micromark-extension-mdxjs-esm'
}
)
error.url =
trouble +
'#unexpected-type-in-code-only-importexports-are-supported'
throw error
}
// Otherwise, when we’re not interrupting (hacky, because `interrupt` is
// used to parse containers and “sniff” if this is ESM), collect all the
// local values that are imported.
if (node.type === 'ImportDeclaration' && !self.interrupt) {
let index = -1
while (++index < node.specifiers.length) {
const specifier = node.specifiers[index]
definedModuleSpecifiers.push(specifier.local.name)
}
}
}
Object.assign(
effects.exit('mdxjsEsm'),
options.addResult ? {estree: result.estree} : undefined
)
return ok(code)
}
}
}
/** @type {Tokenizer} */
function tokenizeNextBlank(effects, ok, nok) {
return start
/**
* @type {State}
*/
function start(code) {
assert(markdownLineEnding(code))
effects.enter(types.lineEndingBlank)
effects.consume(code)
effects.exit(types.lineEndingBlank)
return effects.attempt(blankLine, ok, nok)
}
}