ScopeManager

This document was written based on the implementation of eslint-scope, a fork of 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.