/
explicit-module-boundary-types.ts
481 lines (437 loc) · 13.1 KB
/
explicit-module-boundary-types.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
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
import {
TSESTree,
AST_NODE_TYPES,
AST_TOKEN_TYPES,
} from '@typescript-eslint/experimental-utils';
import * as util from '../util';
type Options = [
{
allowTypedFunctionExpressions?: boolean;
allowHigherOrderFunctions?: boolean;
allowDirectConstAssertionInArrowFunctions?: boolean;
allowedNames?: string[];
},
];
type MessageIds = 'missingReturnType' | 'missingArgType';
export default util.createRule<Options, MessageIds>({
name: 'explicit-module-boundary-types',
meta: {
type: 'problem',
docs: {
description:
"Require explicit return and argument types on exported functions' and classes' public class methods",
category: 'Stylistic Issues',
recommended: false,
},
messages: {
missingReturnType: 'Missing return type on function.',
missingArgType: "Argument '{{name}}' should be typed.",
},
schema: [
{
type: 'object',
properties: {
allowTypedFunctionExpressions: {
type: 'boolean',
},
allowHigherOrderFunctions: {
type: 'boolean',
},
allowDirectConstAssertionInArrowFunctions: {
type: 'boolean',
},
allowedNames: {
type: 'array',
items: {
type: 'string',
},
},
},
additionalProperties: false,
},
],
},
defaultOptions: [
{
allowTypedFunctionExpressions: true,
allowHigherOrderFunctions: true,
allowDirectConstAssertionInArrowFunctions: true,
allowedNames: [],
},
],
create(context, [options]) {
const sourceCode = context.getSourceCode();
/**
* Returns start column position
* @param node
*/
function getLocStart(
node:
| TSESTree.ArrowFunctionExpression
| TSESTree.FunctionDeclaration
| TSESTree.FunctionExpression,
): TSESTree.LineAndColumnData {
/* highlight method name */
const parent = node.parent;
if (
parent &&
(parent.type === AST_NODE_TYPES.MethodDefinition ||
(parent.type === AST_NODE_TYPES.Property && parent.method))
) {
return parent.loc.start;
}
return node.loc.start;
}
/**
* Returns end column position
* @param node
*/
function getLocEnd(
node:
| TSESTree.ArrowFunctionExpression
| TSESTree.FunctionDeclaration
| TSESTree.FunctionExpression,
): TSESTree.LineAndColumnData {
/* highlight `=>` */
if (node.type === AST_NODE_TYPES.ArrowFunctionExpression) {
return sourceCode.getTokenBefore(
node.body,
token =>
token.type === AST_TOKEN_TYPES.Punctuator && token.value === '=>',
)!.loc.end;
}
return sourceCode.getTokenBefore(node.body!)!.loc.end;
}
/**
* Checks if a node is a constructor.
* @param node The node to check
*/
function isConstructor(node: TSESTree.Node | undefined): boolean {
return (
!!node &&
node.type === AST_NODE_TYPES.MethodDefinition &&
node.kind === 'constructor'
);
}
/**
* Checks if a node is a setter.
*/
function isSetter(node: TSESTree.Node | undefined): boolean {
return (
!!node &&
(node.type === AST_NODE_TYPES.MethodDefinition ||
node.type === AST_NODE_TYPES.Property) &&
node.kind === 'set'
);
}
/**
* Checks if a node is a variable declarator with a type annotation.
* `const x: Foo = ...`
*/
function isVariableDeclaratorWithTypeAnnotation(
node: TSESTree.Node,
): boolean {
return (
node.type === AST_NODE_TYPES.VariableDeclarator &&
!!node.id.typeAnnotation
);
}
/**
* Checks if a node is a class property with a type annotation.
* `public x: Foo = ...`
*/
function isClassPropertyWithTypeAnnotation(node: TSESTree.Node): boolean {
return (
node.type === AST_NODE_TYPES.ClassProperty && !!node.typeAnnotation
);
}
/**
* Checks if a node belongs to:
* new Foo(() => {})
* ^^^^^^^^
*/
function isConstructorArgument(parent: TSESTree.Node): boolean {
return parent.type === AST_NODE_TYPES.NewExpression;
}
/**
* Checks if a node is a type cast
* `(() => {}) as Foo`
* `<Foo>(() => {})`
*/
function isTypeCast(node: TSESTree.Node): boolean {
return (
node.type === AST_NODE_TYPES.TSAsExpression ||
node.type === AST_NODE_TYPES.TSTypeAssertion
);
}
/**
* Checks if a node belongs to:
* `const x: Foo = { prop: () => {} }`
* `const x = { prop: () => {} } as Foo`
* `const x = <Foo>{ prop: () => {} }`
*/
function isPropertyOfObjectWithType(
property: TSESTree.Node | undefined,
): boolean {
if (!property || property.type !== AST_NODE_TYPES.Property) {
return false;
}
const objectExpr = property.parent; // this shouldn't happen, checking just in case
/* istanbul ignore if */ if (
!objectExpr ||
objectExpr.type !== AST_NODE_TYPES.ObjectExpression
) {
return false;
}
const parent = objectExpr.parent; // this shouldn't happen, checking just in case
/* istanbul ignore if */ if (!parent) {
return false;
}
return (
isTypeCast(parent) ||
isClassPropertyWithTypeAnnotation(parent) ||
isVariableDeclaratorWithTypeAnnotation(parent) ||
isFunctionArgument(parent)
);
}
function isUnexported(node: TSESTree.Node | undefined): boolean {
let isReturnedValue = false;
while (node) {
if (
node.type === AST_NODE_TYPES.ExportDefaultDeclaration ||
node.type === AST_NODE_TYPES.ExportNamedDeclaration ||
node.type === AST_NODE_TYPES.ExportSpecifier
) {
return false;
}
if (node.type === AST_NODE_TYPES.ReturnStatement) {
isReturnedValue = true;
}
if (
node.type === AST_NODE_TYPES.ArrowFunctionExpression ||
node.type === AST_NODE_TYPES.FunctionDeclaration ||
node.type === AST_NODE_TYPES.FunctionExpression
) {
isReturnedValue = false;
}
if (node.type === AST_NODE_TYPES.BlockStatement && !isReturnedValue) {
return true;
}
node = node.parent;
}
return true;
}
function isPrivateMethod(
node: TSESTree.MethodDefinition | TSESTree.TSAbstractMethodDefinition,
): boolean {
return node.accessibility === 'private';
}
/**
* Checks if a function belongs to:
* `() => () => ...`
* `() => function () { ... }`
* `() => { return () => ... }`
* `() => { return function () { ... } }`
* `function fn() { return () => ... }`
* `function fn() { return function() { ... } }`
*/
function doesImmediatelyReturnFunctionExpression({
body,
}:
| TSESTree.ArrowFunctionExpression
| TSESTree.FunctionDeclaration
| TSESTree.FunctionExpression): boolean {
// Should always have a body; really checking just in case
/* istanbul ignore if */ if (!body) {
return false;
}
// Check if body is a block with a single statement
if (
body.type === AST_NODE_TYPES.BlockStatement &&
body.body.length === 1
) {
const [statement] = body.body;
// Check if that statement is a return statement with an argument
if (
statement.type === AST_NODE_TYPES.ReturnStatement &&
!!statement.argument
) {
// If so, check that returned argument as body
body = statement.argument;
}
}
// Check if the body being returned is a function expression
return (
body.type === AST_NODE_TYPES.ArrowFunctionExpression ||
body.type === AST_NODE_TYPES.FunctionExpression
);
}
/**
* Checks if a node belongs to:
* `foo(() => 1)`
*/
function isFunctionArgument(
parent: TSESTree.Node,
callee?: TSESTree.ArrowFunctionExpression | TSESTree.FunctionExpression,
): boolean {
return (
(parent.type === AST_NODE_TYPES.CallExpression ||
parent.type === AST_NODE_TYPES.OptionalCallExpression) &&
// make sure this isn't an IIFE
parent.callee !== callee
);
}
/**
* Checks if a function belongs to:
* `() => ({ action: 'xxx' }) as const`
*/
function returnsConstAssertionDirectly(
node: TSESTree.ArrowFunctionExpression,
): boolean {
const { body } = node;
if (body.type === AST_NODE_TYPES.TSAsExpression) {
const { typeAnnotation } = body;
if (typeAnnotation.type === AST_NODE_TYPES.TSTypeReference) {
const { typeName } = typeAnnotation;
if (
typeName.type === AST_NODE_TYPES.Identifier &&
typeName.name === 'const'
) {
return true;
}
}
}
return false;
}
/**
* Checks if a function declaration/expression has a return type.
*/
function checkFunctionReturnType(
node:
| TSESTree.ArrowFunctionExpression
| TSESTree.FunctionDeclaration
| TSESTree.FunctionExpression,
): void {
const paramIdentifiers = node.params.filter(
param => param.type === AST_NODE_TYPES.Identifier,
) as TSESTree.Identifier[];
const untypedArgs = paramIdentifiers.filter(isArgumentUntyped);
if (untypedArgs.length) {
untypedArgs.forEach(untypedArg =>
context.report({
node,
messageId: 'missingArgType',
data: {
name: untypedArg.name,
},
}),
);
}
if (isAllowedName(node.parent)) {
return;
}
if (isUnexported(node.parent)) {
return;
}
if (
options.allowHigherOrderFunctions &&
doesImmediatelyReturnFunctionExpression(node)
) {
return;
}
if (
node.returnType ||
isConstructor(node.parent) ||
isSetter(node.parent)
) {
return;
}
context.report({
node,
loc: { start: getLocStart(node), end: getLocEnd(node) },
messageId: 'missingReturnType',
});
}
/**
* Checks if a function declaration/expression has a return type.
*/
function checkFunctionExpressionReturnType(
node: TSESTree.ArrowFunctionExpression | TSESTree.FunctionExpression,
): void {
// Should always have a parent; checking just in case
/* istanbul ignore else */ if (node.parent) {
if (
node.parent.type === AST_NODE_TYPES.MethodDefinition &&
isPrivateMethod(node.parent)
) {
return;
}
if (options.allowTypedFunctionExpressions) {
if (
isTypeCast(node.parent) ||
isVariableDeclaratorWithTypeAnnotation(node.parent) ||
isClassPropertyWithTypeAnnotation(node.parent) ||
isPropertyOfObjectWithType(node.parent) ||
isFunctionArgument(node.parent, node) ||
isConstructorArgument(node.parent)
) {
return;
}
}
}
if (
node.type === AST_NODE_TYPES.ArrowFunctionExpression &&
options.allowDirectConstAssertionInArrowFunctions &&
returnsConstAssertionDirectly(node)
) {
return;
}
checkFunctionReturnType(node);
}
/**
* Checks if a function name is allowed and should not be checked.
*/
function isAllowedName(node: TSESTree.Node | undefined): boolean {
if (!node || !options.allowedNames || !options.allowedNames.length) {
return false;
}
if (node.type === AST_NODE_TYPES.VariableDeclarator) {
return (
node.id.type === AST_NODE_TYPES.Identifier &&
options.allowedNames.includes(node.id.name)
);
} else if (
node.type === AST_NODE_TYPES.MethodDefinition ||
node.type === AST_NODE_TYPES.TSAbstractMethodDefinition
) {
if (
node.key.type === AST_NODE_TYPES.Literal &&
typeof node.key.value === 'string'
) {
return options.allowedNames.includes(node.key.value);
}
if (
node.key.type === AST_NODE_TYPES.TemplateLiteral &&
node.key.expressions.length === 0
) {
return options.allowedNames.includes(node.key.quasis[0].value.raw);
}
if (!node.computed && node.key.type === AST_NODE_TYPES.Identifier) {
return options.allowedNames.includes(node.key.name);
}
}
return false;
}
function isArgumentUntyped(node: TSESTree.Identifier): boolean {
return (
!node.typeAnnotation ||
node.typeAnnotation.typeAnnotation.type === AST_NODE_TYPES.TSAnyKeyword
);
}
return {
ArrowFunctionExpression: checkFunctionExpressionReturnType,
FunctionDeclaration: checkFunctionReturnType,
FunctionExpression: checkFunctionExpressionReturnType,
};
},
});