eslint/docs/src/developer-guide/scope-manager-interface.md

   1 ---
   2 title: ScopeManager
   3 layout: doc
   4
   5 ---
   6
   7 This document was written based on the implementation of [eslint-scope](https://github.com/eslint/eslint-scope), a fork of [escope](https://github.com/estools/escope), and deprecates some members ESLint is not using.
   8
   9 ----
  10
  11 ## ScopeManager interface
  12
  13 `ScopeManager` object has all variable scopes.
  14
  15 ### Fields
  16
  17 #### scopes
  18
  19 * **Type:** `Scope[]`
  20 * **Description:** All scopes.
  21
  22 #### globalScope
  23
  24 * **Type:** `Scope`
  25 * **Description:** The root scope.
  26
  27 ### Methods
  28
  29 #### acquire(node, inner = false)
  30
  31 * **Parameters:**
  32     * `node` (`ASTNode`) ... An AST node to get their scope.
  33     * `inner` (`boolean`) ... If the node has multiple scope, this returns the outermost scope normally. If `inner` is `true` then this returns the innermost scope. Default is `false`.
  34 * **Return type:** `Scope | null`
  35 * **Description:** Get the scope of a given AST node. The gotten scope's `block` property is the node. This method never returns `function-expression-name` scope. If the node does not have their scope, this returns `null`.
  36
  37 #### getDeclaredVariables(node)
  38
  39 * **Parameters:**
  40     * `node` (`ASTNode`) ... An AST node to get their variables.
  41 * **Return type:** `Variable[]`
  42 * **Description:** Get the variables that a given AST node defines. The gotten variables' `def[].node`/`def[].parent` property is the node. If the node does not define any variable, this returns an empty array.
  43
  44 ### Deprecated members
  45
  46 Those members are defined but not used in ESLint.
  47
  48 #### isModule()
  49
  50 * **Parameters:**
  51 * **Return type:** `boolean`
  52 * **Description:** `true` if this program is module.
  53
  54 #### isImpliedStrict()
  55
  56 * **Parameters:**
  57 * **Return type:** `boolean`
  58 * **Description:** `true` if this program is strict mode implicitly. I.e., `options.impliedStrict === true`.
  59
  60 #### isStrictModeSupported()
  61
  62 * **Parameters:**
  63 * **Return type:** `boolean`
  64 * **Description:** `true` if this program supports strict mode. I.e., `options.ecmaVersion >= 5`.
  65
  66 #### acquireAll(node)
  67
  68 * **Parameters:**
  69     * `node` (`ASTNode`) ... An AST node to get their scope.
  70 * **Return type:** `Scope[] | null`
  71 * **Description:** Get the scopes of a given AST node. The gotten scopes' `block` property is the node. If the node does not have their scope, this returns `null`.
  72
  73 ----
  74
  75 ## Scope interface
  76
  77 `Scope` object has all variables and references in the scope.
  78
  79 ### Fields
  80
  81 #### type
  82
  83 * **Type:** `string`
  84 * **Description:** The type of this scope. This is one of `"block"`, `"catch"`, `"class"`, `"class-field-initializer"`, `"class-static-block"`, `"for"`, `"function"`, `"function-expression-name"`, `"global"`, `"module"`, `"switch"`, `"with"`.
  85
  86 #### isStrict
  87
  88 * **Type:** `boolean`
  89 * **Description:** `true` if this scope is strict mode.
  90
  91 #### upper
  92
  93 * **Type:** `Scope | null`
  94 * **Description:** The parent scope. If this is the global scope then this property is `null`.
  95
  96 #### childScopes
  97
  98 * **Type:** `Scope[]`
  99 * **Description:** The array of child scopes. This does not include grandchild scopes.
 100
 101 #### variableScope
 102
 103 * **Type:** `Scope`
 104 * **Description:** The nearest ancestor whose `type` is one of `"class-field-initializer"`, `"class-static-block"`, `"function"`, `"global"`, or `"module"`. For the aforementioned scopes this is a self-reference.
 105
 106 > This represents the lowest enclosing function or top-level scope. Class field initializers and class static blocks are implicit functions. Historically, this was the scope which hosts variables that are defined by `var` declarations, and thus the name `variableScope`.
 107
 108 #### block
 109
 110 * **Type:** `ASTNode`
 111 * **Description:** The AST node which created this scope.
 112
 113 #### variables
 114
 115 * **Type:** `Variable[]`
 116 * **Description:** The array of all variables which are defined on this scope. This does not include variables which are defined in child scopes.
 117
 118 #### set
 119
 120 * **Type:** `Map<string, Variable>`
 121 * **Description:** The map from variable names to variable objects.
 122
 123 > I hope to rename `set` field or replace by a method.
 124
 125 #### references
 126
 127 * **Type:** `Reference[]`
 128 * **Description:** The array of all references on this scope. This does not include references in child scopes.
 129
 130 #### through
 131
 132 * **Type:** `Reference[]`
 133 * **Description:** The array of references which could not be resolved in this scope.
 134
 135 #### functionExpressionScope
 136
 137 * **Type:** `boolean`
 138 * **Description:** `true` if this scope is `"function-expression-name"` scope.
 139
 140 > I hope to deprecate `functionExpressionScope` field as replacing by `scope.type === "function-expression-name"`.
 141
 142 ### Deprecated members
 143
 144 Those members are defined but not used in ESLint.
 145
 146 #### taints
 147
 148 * **Type:** `Map<string, boolean>`
 149 * **Description:** The map from variable names to `tainted` flag.
 150
 151 #### dynamic
 152
 153 * **Type:** `boolean`
 154 * **Description:** `true` if this scope is dynamic. I.e., the type of this scope is `"global"` or `"with"`.
 155
 156 #### directCallToEvalScope
 157
 158 * **Type:** `boolean`
 159 * **Description:** `true` if this scope contains `eval()` invocations.
 160
 161 #### thisFound
 162
 163 * **Type:** `boolean`
 164 * **Description:** `true` if this scope contains `this`.
 165
 166 #### resolve(node)
 167
 168 * **Parameters:**
 169     * `node` (`ASTNode`) ... An AST node to get their reference object. The type of the node must be `"Identifier"`.
 170 * **Return type:** `Reference | null`
 171 * **Description:** Returns `this.references.find(r => r.identifier === node)`.
 172
 173 #### isStatic()
 174
 175 * **Parameters:**
 176 * **Return type:** `boolean`
 177 * **Description:** Returns `!this.dynamic`.
 178
 179 #### isArgumentsMaterialized()
 180
 181 * **Parameters:**
 182 * **Return type:** `boolean`
 183 * **Description:** `true` if this is a `"function"` scope which has used `arguments` variable.
 184
 185 #### isThisMaterialized()
 186
 187 * **Parameters:**
 188 * **Return type:** `boolean`
 189 * **Description:** Returns `this.thisFound`.
 190
 191 #### isUsedName(name)
 192
 193 * **Parameters:**
 194     * `name` (`string`) ... The name to check.
 195 * **Return type:** `boolean`
 196 * **Description:** `true` if a given name is used in variable names or reference names.
 197
 198 ----
 199
 200 ## Variable interface
 201
 202 `Variable` object is variable's information.
 203
 204 ### Fields
 205
 206 #### name
 207
 208 * **Type:** `string`
 209 * **Description:** The name of this variable.
 210
 211 #### scope
 212
 213 * **Type:** `Scope`
 214 * **Description:** The scope in which this variable is defined.
 215
 216 #### identifiers
 217
 218 * **Type:** `ASTNode[]`
 219 * **Description:** The array of `Identifier` nodes which define this variable. If this variable is redeclared, this array includes two or more nodes.
 220
 221 > I hope to deprecate `identifiers` field as replacing by `defs[].name` field.
 222
 223 #### references
 224
 225 * **Type:** `Reference[]`
 226 * **Description:** The array of the references of this variable.
 227
 228 #### defs
 229
 230 * **Type:** `Definition[]`
 231 * **Description:** The array of the definitions of this variable.
 232
 233 ### Deprecated members
 234
 235 Those members are defined but not used in ESLint.
 236
 237 #### tainted
 238
 239 * **Type:** `boolean`
 240 * **Description:** The `tainted` flag. (always `false`)
 241
 242 #### stack
 243
 244 * **Type:** `boolean`
 245 * **Description:** The `stack` flag. (I'm not sure what this means.)
 246
 247 ----
 248
 249 ## Reference interface
 250
 251 `Reference` object is reference's information.
 252
 253 ### Fields
 254
 255 #### identifier
 256
 257 * **Type:** `ASTNode`
 258 * **Description:** The `Identifier` node of this reference.
 259
 260 #### from
 261
 262 * **Type:** `Scope`
 263 * **Description:** The `Scope` object that this reference is on.
 264
 265 #### resolved
 266
 267 * **Type:** `Variable | null`
 268 * **Description:** The `Variable` object that this reference refers. If such variable was not defined, this is `null`.
 269
 270 #### writeExpr
 271
 272 * **Type:** `ASTNode | null`
 273 * **Description:** The ASTNode object which is right-hand side.
 274
 275 #### init
 276
 277 * **Type:** `boolean`
 278 * **Description:** `true` if this writing reference is a variable initializer or a default value.
 279
 280 ### Methods
 281
 282 #### isWrite()
 283
 284 * **Parameters:**
 285 * **Return type:** `boolean`
 286 * **Description:** `true` if this reference is writing.
 287
 288 #### isRead()
 289
 290 * **Parameters:**
 291 * **Return type:** `boolean`
 292 * **Description:** `true` if this reference is reading.
 293
 294 #### isWriteOnly()
 295
 296 * **Parameters:**
 297 * **Return type:** `boolean`
 298 * **Description:** `true` if this reference is writing but not reading.
 299
 300 #### isReadOnly()
 301
 302 * **Parameters:**
 303 * **Return type:** `boolean`
 304 * **Description:** `true` if this reference is reading but not writing.
 305
 306 #### isReadWrite()
 307
 308 * **Parameters:**
 309 * **Return type:** `boolean`
 310 * **Description:** `true` if this reference is reading and writing.
 311
 312 ### Deprecated members
 313
 314 Those members are defined but not used in ESLint.
 315
 316 #### tainted
 317
 318 * **Type:** `boolean`
 319 * **Description:** The `tainted` flag. (always `false`)
 320
 321 #### flag
 322
 323 * **Type:** `number`
 324 * **Description:** `1` is reading, `2` is writing, `3` is reading/writing.
 325
 326 #### partial
 327
 328 * **Type:** `boolean`
 329 * **Description:** The `partial` flag.
 330
 331 #### isStatic()
 332
 333 * **Parameters:**
 334 * **Return type:** `boolean`
 335 * **Description:** `true` if this reference is resolved statically.
 336
 337 ----
 338
 339 ## Definition interface
 340
 341 `Definition` object is variable definition's information.
 342
 343 ### Fields
 344
 345 #### type
 346
 347 * **Type:** `string`
 348 * **Description:** The type of this definition. One of `"CatchClause"`, `"ClassName"`, `"FunctionName"`, `"ImplicitGlobalVariable"`, `"ImportBinding"`, `"Parameter"`, and `"Variable"`.
 349
 350 #### name
 351
 352 * **Type:** `ASTNode`
 353 * **Description:** The `Identifier` node of this definition.
 354
 355 #### node
 356
 357 * **Type:** `ASTNode`
 358 * **Description:** The enclosing node of the name.
 359
 360 | type                       | node |
 361 |:---------------------------|:-----|
 362 | `"CatchClause"`            | `CatchClause`
 363 | `"ClassName"`              | `ClassDeclaration` or `ClassExpression`
 364 | `"FunctionName"`           | `FunctionDeclaration` or `FunctionExpression`
 365 | `"ImplicitGlobalVariable"` | `Program`
 366 | `"ImportBinding"`          | `ImportSpecifier`, `ImportDefaultSpecifier`, or `ImportNamespaceSpecifier`
 367 | `"Parameter"`              | `FunctionDeclaration`, `FunctionExpression`, or `ArrowFunctionExpression`
 368 | `"Variable"`               | `VariableDeclarator`
 369
 370 #### parent
 371
 372 * **Type:** `ASTNode | undefined | null`
 373 * **Description:** The enclosing statement node of the name.
 374
 375 | type                       | parent |
 376 |:---------------------------|:-------|
 377 | `"CatchClause"`            | `null`
 378 | `"ClassName"`              | `null`
 379 | `"FunctionName"`           | `null`
 380 | `"ImplicitGlobalVariable"` | `null`
 381 | `"ImportBinding"`          | `ImportDeclaration`
 382 | `"Parameter"`              | `null`
 383 | `"Variable"`               | `VariableDeclaration`
 384
 385 ### Deprecated members
 386
 387 Those members are defined but not used in ESLint.
 388
 389 #### index
 390
 391 * **Type:** `number | undefined | null`
 392 * **Description:** The index in the declaration statement.
 393
 394 #### kind
 395
 396 * **Type:** `string | undefined | null`
 397 * **Description:** The kind of the declaration statement.