[pve-eslint.git] / eslint / docs / src / extend / scope-manager-interface.md

---
title: ScopeManager

---

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.

----

## ScopeManager interface

`ScopeManager` object has all variable scopes.

### Fields

#### scopes

* **Type:** `Scope[]`
* **Description:** All scopes.

#### globalScope

* **Type:** `Scope`
* **Description:** The root scope.

### Methods

#### acquire(node, inner = false)

* **Parameters:**
    * `node` (`ASTNode`) ... An AST node to get their scope.
    * `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`.
* **Return type:** `Scope | null`
* **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`.

#### getDeclaredVariables(node)

* **Parameters:**
    * `node` (`ASTNode`) ... An AST node to get their variables.
* **Return type:** `Variable[]`
* **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.

### Deprecated members

Those members are defined but not used in ESLint.

#### isModule()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this program is module.

#### isImpliedStrict()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this program is strict mode implicitly. I.e., `options.impliedStrict === true`.

#### isStrictModeSupported()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this program supports strict mode. I.e., `options.ecmaVersion >= 5`.

#### acquireAll(node)

* **Parameters:**
    * `node` (`ASTNode`) ... An AST node to get their scope.
* **Return type:** `Scope[] | null`
* **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`.

----

## Scope interface

`Scope` object has all variables and references in the scope.

### Fields

#### type

* **Type:** `string`
* **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"`.

#### isStrict

* **Type:** `boolean`
* **Description:** `true` if this scope is strict mode.

#### upper

* **Type:** `Scope | null`
* **Description:** The parent scope. If this is the global scope then this property is `null`.

#### childScopes

* **Type:** `Scope[]`
* **Description:** The array of child scopes. This does not include grandchild scopes.

#### variableScope

* **Type:** `Scope`
* **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.

> 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`.

#### block

* **Type:** `ASTNode`
* **Description:** The AST node which created this scope.

#### variables

* **Type:** `Variable[]`
* **Description:** The array of all variables which are defined on this scope. This does not include variables which are defined in child scopes.

#### set

* **Type:** `Map<string, Variable>`
* **Description:** The map from variable names to variable objects.

> I hope to rename `set` field or replace by a method.

#### references

* **Type:** `Reference[]`
* **Description:** The array of all references on this scope. This does not include references in child scopes.

#### through

* **Type:** `Reference[]`
* **Description:** The array of references which could not be resolved in this scope.

#### functionExpressionScope

* **Type:** `boolean`
* **Description:** `true` if this scope is `"function-expression-name"` scope.

> I hope to deprecate `functionExpressionScope` field as replacing by `scope.type === "function-expression-name"`.

### Deprecated members

Those members are defined but not used in ESLint.

#### taints

* **Type:** `Map<string, boolean>`
* **Description:** The map from variable names to `tainted` flag.

#### dynamic

* **Type:** `boolean`
* **Description:** `true` if this scope is dynamic. I.e., the type of this scope is `"global"` or `"with"`.

#### directCallToEvalScope

* **Type:** `boolean`
* **Description:** `true` if this scope contains `eval()` invocations.

#### thisFound

* **Type:** `boolean`
* **Description:** `true` if this scope contains `this`.

#### resolve(node)

* **Parameters:**
    * `node` (`ASTNode`) ... An AST node to get their reference object. The type of the node must be `"Identifier"`.
* **Return type:** `Reference | null`
* **Description:** Returns `this.references.find(r => r.identifier === node)`.

#### isStatic()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** Returns `!this.dynamic`.

#### isArgumentsMaterialized()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this is a `"function"` scope which has used `arguments` variable.

#### isThisMaterialized()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** Returns `this.thisFound`.

#### isUsedName(name)

* **Parameters:**
    * `name` (`string`) ... The name to check.
* **Return type:** `boolean`
* **Description:** `true` if a given name is used in variable names or reference names.

----

## Variable interface

`Variable` object is variable's information.

### Fields

#### name

* **Type:** `string`
* **Description:** The name of this variable.

#### scope

* **Type:** `Scope`
* **Description:** The scope in which this variable is defined.

#### identifiers

* **Type:** `ASTNode[]`
* **Description:** The array of `Identifier` nodes which define this variable. If this variable is redeclared, this array includes two or more nodes.

> I hope to deprecate `identifiers` field as replacing by `defs[].name` field.

#### references

* **Type:** `Reference[]`
* **Description:** The array of the references of this variable.

#### defs

* **Type:** `Definition[]`
* **Description:** The array of the definitions of this variable.

### Deprecated members

Those members are defined but not used in ESLint.

#### tainted

* **Type:** `boolean`
* **Description:** The `tainted` flag. (always `false`)

#### stack

* **Type:** `boolean`
* **Description:** The `stack` flag. (I'm not sure what this means.)

----

## Reference interface

`Reference` object is reference's information.

### Fields

#### identifier

* **Type:** `ASTNode`
* **Description:** The `Identifier` node of this reference.

#### from

* **Type:** `Scope`
* **Description:** The `Scope` object that this reference is on.

#### resolved

* **Type:** `Variable | null`
* **Description:** The `Variable` object that this reference refers. If such variable was not defined, this is `null`.

#### writeExpr

* **Type:** `ASTNode | null`
* **Description:** The ASTNode object which is right-hand side.

#### init

* **Type:** `boolean`
* **Description:** `true` if this writing reference is a variable initializer or a default value.

### Methods

#### isWrite()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is writing.

#### isRead()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is reading.

#### isWriteOnly()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is writing but not reading.

#### isReadOnly()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is reading but not writing.

#### isReadWrite()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is reading and writing.

### Deprecated members

Those members are defined but not used in ESLint.

#### tainted

* **Type:** `boolean`
* **Description:** The `tainted` flag. (always `false`)

#### flag

* **Type:** `number`
* **Description:** `1` is reading, `2` is writing, `3` is reading/writing.

#### partial

* **Type:** `boolean`
* **Description:** The `partial` flag.

#### isStatic()

* **Parameters:**
* **Return type:** `boolean`
* **Description:** `true` if this reference is resolved statically.

----

## Definition interface

`Definition` object is variable definition's information.

### Fields

#### type

* **Type:** `string`
* **Description:** The type of this definition. One of `"CatchClause"`, `"ClassName"`, `"FunctionName"`, `"ImplicitGlobalVariable"`, `"ImportBinding"`, `"Parameter"`, and `"Variable"`.

#### name

* **Type:** `ASTNode`
* **Description:** The `Identifier` node of this definition.

#### node

* **Type:** `ASTNode`
* **Description:** The enclosing node of the name.

| type                       | node |
|:---------------------------|:-----|
| `"CatchClause"`            | `CatchClause`
| `"ClassName"`              | `ClassDeclaration` or `ClassExpression`
| `"FunctionName"`           | `FunctionDeclaration` or `FunctionExpression`
| `"ImplicitGlobalVariable"` | `Program`
| `"ImportBinding"`          | `ImportSpecifier`, `ImportDefaultSpecifier`, or `ImportNamespaceSpecifier`
| `"Parameter"`              | `FunctionDeclaration`, `FunctionExpression`, or `ArrowFunctionExpression`
| `"Variable"`               | `VariableDeclarator`

#### parent

* **Type:** `ASTNode | undefined | null`
* **Description:** The enclosing statement node of the name.

| type                       | parent |
|:---------------------------|:-------|
| `"CatchClause"`            | `null`
| `"ClassName"`              | `null`
| `"FunctionName"`           | `null`
| `"ImplicitGlobalVariable"` | `null`
| `"ImportBinding"`          | `ImportDeclaration`
| `"Parameter"`              | `null`
| `"Variable"`               | `VariableDeclaration`

### Deprecated members

Those members are defined but not used in ESLint.

#### index

* **Type:** `number | undefined | null`
* **Description:** The index in the declaration statement.

#### kind

* **Type:** `string | undefined | null`
* **Description:** The kind of the declaration statement.
Commit	Line	Data
8f9d1d4d DC	1	---
8f9d1d4d DC	2	title: ScopeManager
8f9d1d4d DC	3
8f9d1d4d DC	4	---
eb39fafa DC	5
	6	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.
	7
	8	----
	9
	10	## ScopeManager interface
	11
	12	`ScopeManager` object has all variable scopes.
	13
	14	### Fields
	15
	16	#### scopes
	17
	18	* Type: `Scope[]`
	19	* Description: All scopes.
	20
	21	#### globalScope
	22
	23	* Type: `Scope`
	24	* Description: The root scope.
	25
	26	### Methods
	27
	28	#### acquire(node, inner = false)
	29
	30	* Parameters:
	31	* `node` (`ASTNode`) ... An AST node to get their scope.
	32	* `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`.
	33	* Return type: `Scope \| null`
	34	* 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`.
	35
	36	#### getDeclaredVariables(node)
	37
	38	* Parameters:
	39	* `node` (`ASTNode`) ... An AST node to get their variables.
	40	* Return type: `Variable[]`
	41	* 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.
	42
	43	### Deprecated members
	44
	45	Those members are defined but not used in ESLint.
	46
	47	#### isModule()
	48
	49	* Parameters:
	50	* Return type: `boolean`
	51	* Description: `true` if this program is module.
	52
	53	#### isImpliedStrict()
	54
	55	* Parameters:
	56	* Return type: `boolean`
	57	* Description: `true` if this program is strict mode implicitly. I.e., `options.impliedStrict === true`.
	58
	59	#### isStrictModeSupported()
	60
	61	* Parameters:
	62	* Return type: `boolean`
	63	* Description: `true` if this program supports strict mode. I.e., `options.ecmaVersion >= 5`.
	64
	65	#### acquireAll(node)
	66
	67	* Parameters:
	68	* `node` (`ASTNode`) ... An AST node to get their scope.
69	* Return type: `Scope[] \| null`
70	* 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`.
71
72	----
73
74	## Scope interface
75
76	`Scope` object has all variables and references in the scope.
77
78	### Fields
79
80	#### type
81
82	* Type: `string`
609c276f	83	* 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"`.
eb39fafa DC	84
	85	#### isStrict
	86
	87	* Type: `boolean`
	88	* Description: `true` if this scope is strict mode.
	89
	90	#### upper
	91
	92	* Type: `Scope \| null`
	93	* Description: The parent scope. If this is the global scope then this property is `null`.
	94
	95	#### childScopes
	96
	97	* Type: `Scope[]`
	98	* Description: The array of child scopes. This does not include grandchild scopes.
	99
	100	#### variableScope
	101
	102	* Type: `Scope`
609c276f TL	103	* 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.
	104
	105	> 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`.
eb39fafa DC	106
	107	#### block
	108
	109	* Type: `ASTNode`
	110	* Description: The AST node which created this scope.
	111
	112	#### variables
	113
	114	* Type: `Variable[]`
	115	* Description: The array of all variables which are defined on this scope. This does not include variables which are defined in child scopes.
	116
	117	#### set
	118
	119	* Type: `Map<string, Variable>`
	120	* Description: The map from variable names to variable objects.
	121
	122	> I hope to rename `set` field or replace by a method.
	123
	124	#### references
	125
	126	* Type: `Reference[]`
	127	* Description: The array of all references on this scope. This does not include references in child scopes.
	128
	129	#### through
	130
	131	* Type: `Reference[]`
	132	* Description: The array of references which could not be resolved in this scope.
	133
	134	#### functionExpressionScope
	135
	136	* Type: `boolean`
	137	* Description: `true` if this scope is `"function-expression-name"` scope.
	138
	139	> I hope to deprecate `functionExpressionScope` field as replacing by `scope.type === "function-expression-name"`.
	140
	141	### Deprecated members
	142
	143	Those members are defined but not used in ESLint.
	144
	145	#### taints
	146
	147	* Type: `Map<string, boolean>`
	148	* Description: The map from variable names to `tainted` flag.
	149
	150	#### dynamic
	151
	152	* Type: `boolean`
	153	* Description: `true` if this scope is dynamic. I.e., the type of this scope is `"global"` or `"with"`.
	154
	155	#### directCallToEvalScope
	156
	157	* Type: `boolean`
	158	* Description: `true` if this scope contains `eval()` invocations.
	159
	160	#### thisFound
	161
	162	* Type: `boolean`
	163	* Description: `true` if this scope contains `this`.
	164
	165	#### resolve(node)
	166
	167	* Parameters:
	168	* `node` (`ASTNode`) ... An AST node to get their reference object. The type of the node must be `"Identifier"`.
	169	* Return type: `Reference \| null`
170	* Description: Returns `this.references.find(r => r.identifier === node)`.
171
172	#### isStatic()
173
174	* Parameters:
175	* Return type: `boolean`
176	* Description: Returns `!this.dynamic`.
177
178	#### isArgumentsMaterialized()
179
180	* Parameters:
181	* Return type: `boolean`
182	* Description: `true` if this is a `"function"` scope which has used `arguments` variable.
183
184	#### isThisMaterialized()
185
186	* Parameters:
187	* Return type: `boolean`
188	* Description: Returns `this.thisFound`.
189
190	#### isUsedName(name)
191
192	* Parameters:
193	* `name` (`string`) ... The name to check.
194	* Return type: `boolean`
195	* Description: `true` if a given name is used in variable names or reference names.
196
197	----
198
199	## Variable interface
200
201	`Variable` object is variable's information.
202
203	### Fields
204
205	#### name
206
207	* Type: `string`
208	* Description: The name of this variable.
209
8f9d1d4d DC	210	#### scope
	211
	212	* Type: `Scope`
	213	* Description: The scope in which this variable is defined.
	214
eb39fafa DC	215	#### identifiers
	216
	217	* Type: `ASTNode[]`
	218	* Description: The array of `Identifier` nodes which define this variable. If this variable is redeclared, this array includes two or more nodes.
	219
	220	> I hope to deprecate `identifiers` field as replacing by `defs[].name` field.
	221
	222	#### references
	223
	224	* Type: `Reference[]`
	225	* Description: The array of the references of this variable.
	226
	227	#### defs
	228
	229	* Type: `Definition[]`
	230	* Description: The array of the definitions of this variable.
	231
	232	### Deprecated members
	233
	234	Those members are defined but not used in ESLint.
	235
	236	#### tainted
	237
	238	* Type: `boolean`
	239	* Description: The `tainted` flag. (always `false`)
	240
	241	#### stack
	242
	243	* Type: `boolean`
	244	* Description: The `stack` flag. (I'm not sure what this means.)
	245
	246	----
	247
	248	## Reference interface
	249
	250	`Reference` object is reference's information.
	251
	252	### Fields
	253
	254	#### identifier
	255
	256	* Type: `ASTNode`
	257	* Description: The `Identifier` node of this reference.
	258
	259	#### from
	260
	261	* Type: `Scope`
	262	* Description: The `Scope` object that this reference is on.
	263
	264	#### resolved
	265
	266	* Type: `Variable \| null`
	267	* Description: The `Variable` object that this reference refers. If such variable was not defined, this is `null`.
	268
	269	#### writeExpr
	270
	271	* Type: `ASTNode \| null`
	272	* Description: The ASTNode object which is right-hand side.
	273
	274	#### init
	275
	276	* Type: `boolean`
	277	* Description: `true` if this writing reference is a variable initializer or a default value.
	278
279	### Methods
280
281	#### isWrite()
282
283	* Parameters:
284	* Return type: `boolean`
285	* Description: `true` if this reference is writing.
286
287	#### isRead()
288
289	* Parameters:
290	* Return type: `boolean`
291	* Description: `true` if this reference is reading.
292
293	#### isWriteOnly()
294
295	* Parameters:
296	* Return type: `boolean`
297	* Description: `true` if this reference is writing but not reading.
298
299	#### isReadOnly()
300
301	* Parameters:
302	* Return type: `boolean`
303	* Description: `true` if this reference is reading but not writing.
304
305	#### isReadWrite()
306
307	* Parameters:
308	* Return type: `boolean`
309	* Description: `true` if this reference is reading and writing.
310
311	### Deprecated members
312
313	Those members are defined but not used in ESLint.
314
315	#### tainted
316
317	* Type: `boolean`
318	* Description: The `tainted` flag. (always `false`)
319
320	#### flag
321
322	* Type: `number`
323	* Description: `1` is reading, `2` is writing, `3` is reading/writing.
324
325	#### partial
326
327	* Type: `boolean`
328	* Description: The `partial` flag.
329
330	#### isStatic()
331
332	* Parameters:
333	* Return type: `boolean`
334	* Description: `true` if this reference is resolved statically.
335
336	----
337
338	## Definition interface
339
340	`Definition` object is variable definition's information.
341
342	### Fields
343
344	#### type
345
346	* Type: `string`
347	* Description: The type of this definition. One of `"CatchClause"`, `"ClassName"`, `"FunctionName"`, `"ImplicitGlobalVariable"`, `"ImportBinding"`, `"Parameter"`, and `"Variable"`.
348
349	#### name
350
351	* Type: `ASTNode`
352	* Description: The `Identifier` node of this definition.
353
354	#### node
355
356	* Type: `ASTNode`
357	* Description: The enclosing node of the name.
358
359	\| type \| node \|
360	\|:---------------------------\|:-----\|
361	\| `"CatchClause"` \| `CatchClause`
362	\| `"ClassName"` \| `ClassDeclaration` or `ClassExpression`
363	\| `"FunctionName"` \| `FunctionDeclaration` or `FunctionExpression`
364	\| `"ImplicitGlobalVariable"` \| `Program`
365	\| `"ImportBinding"` \| `ImportSpecifier`, `ImportDefaultSpecifier`, or `ImportNamespaceSpecifier`
366	\| `"Parameter"` \| `FunctionDeclaration`, `FunctionExpression`, or `ArrowFunctionExpression`
367	\| `"Variable"` \| `VariableDeclarator`
368
369	#### parent
370
371	* Type: `ASTNode \| undefined \| null`
372	* Description: The enclosing statement node of the name.
373
374	\| type \| parent \|
375	\|:---------------------------\|:-------\|
376	\| `"CatchClause"` \| `null`
377	\| `"ClassName"` \| `null`
378	\| `"FunctionName"` \| `null`
379	\| `"ImplicitGlobalVariable"` \| `null`
380	\| `"ImportBinding"` \| `ImportDeclaration`
381	\| `"Parameter"` \| `null`
382	\| `"Variable"` \| `VariableDeclaration`
383
384	### Deprecated members
385
386	Those members are defined but not used in ESLint.
387
388	#### index
389
390	* Type: `number \| undefined \| null`
391	* Description: The index in the declaration statement.
392
393	#### kind
394
395	* Type: `string \| undefined \| null`
396	* Description: The kind of the declaration statement.