Expressions and Patterns

A binding pattern can be one of the following:

type BindingPattern = ArrayPattern | ObjectPattern;

An expression can be one of the following:

type Expression = ThisExpression | Identifier | Literal |
    ArrayExpression | ObjectExpression | FunctionExpression | ArrowFunctionExpression | ClassExpression |
    TaggedTemplateExpression | MemberExpression | Super | MetaProperty |
    NewExpression | CallExpression | UpdateExpression | UnaryExpression |
    BinaryExpression | LogicalExpression | ConditionalExpression |
    YieldExpression | AssignmentExpression | SequenceExpression;

Array Pattern

interface ArrayPattern {
    type: 'ArrayPattern';
    elements: ArrayPatternElement[];
}

with

type ArrayPatternElement = AssignmentPattern | Identifier | BindingPattern | RestElement | null;
 
interface RestElement {
    type: 'RestElement';
    argument: Identifier | BindingPattern;
}

Assignment Pattern

interface AssignmentPattern {
    type: 'AssignmentPattern';
    left: Identifier | BindingPattern;
    right: Expression;
}

Object Pattern

interface ObjectPattern {
    type: 'ObjectPattern';
    properties: Property[];
}

This Expression

interface ThisExpression {
    type: 'ThisExpression';
}

Identifier

interface Identifier {
    type: 'Identifier';
    name: string;
}

Literal

interface Literal {
    type: 'Literal';
    value: boolean | number | string | RegExp | null;
    raw: string;
    regex?: { pattern: string, flags: string };
}

The regex property only applies to regular expression literals.

Array Expression

interface ArrayExpression {
    type: 'ArrayExpression';
    elements: ArrayExpressionElement[];
}

where

type ArrayExpressionElement = Expression | SpreadElement;

Object Expression

interface ObjectExpression {
    type: 'ObjectExpression';
    properties: Property[];
}

where

interface Property {
    type: 'Property';
    key: Identifier | Literal;
    computed: boolean;
    value: AssignmentPattern | Identifier | BindingPattern | FunctionExpression | null;
    kind: 'get' | 'set' | 'init';
    method: false;
    shorthand: boolean;
}

Function Expression

interface FunctionExpression {
    type: 'FunctionExpression';
    id: Identifier | null;
    params: FunctionParameter[];
    body: BlockStatement;
    generator: boolean;
    expression: boolean;
}

with

type FunctionParameter = AssignmentPattern | Identifier | BindingPattern;

The value of generator is true for a generator expression.

Arrow Function Expression

interface FunctionExpression {
    type: 'ArrowFunctionExpression';
    id: Identifier | null;
    params: FunctionParameter[];
    body: BlockStatement | Expression;
    generator: boolean;
    expression: false;
}

Class Expression

interface ClassExpression {
    type: 'ClassExpression';
    id: Identifier | null;
    superClass: Identifier | null;
    body: ClassBody;

with

interface ClassBody {
    type: 'ClassBody';
    body: MethodDefinition[];
}
 
interface MethodDefinition {
    type: 'MethodDefinition';
    key: Expression | null;
    computed: boolean;
    value: FunctionExpression | null;
    kind: 'method' | 'constructor';
    static: boolean;
}

Tagged Template Expression

interface TaggedTemplateExpression {
    type: 'TaggedTemplateExpression';
    readonly tag: Expression;
    readonly quasi: TemplateLiteral;
}

with

interface TemplateElement {
    type: 'TemplateElement';
    value: { cooked: string; raw: string };
    tail: boolean;
}
 
interface TemplateLiteral {
    type: 'TemplateLiteral';
    quasis: TemplateElement[];
    expressions: Expression[];
}

Member Expression

interface MemberExpression {
    type: 'MemberExpression';
    computed: boolean;
    object: Expression;
    property: Expression;
}

Super

interface Super {
    type: 'Super';
}

MetaProperty

interface MetaProperty {
    type: 'MetaProperty';
    meta: Identifier;
    property: Identifier;
}

Call and New Expressions

interface CallExpression {
    type: 'CallExpression';
    callee: Expression;
    arguments: ArgumentListElement[];
}
 
interface NewExpression {
    type: 'NewExpression';
    callee: Expression;
    arguments: ArgumentListElement[];
}

with

type ArgumentListElement = Expression | SpreadElement;
 
interface SpreadElement {
    type: 'SpreadElement';
    argument: Expression;
}

Update Expression

interface UpdateExpression {
    type: 'UpdateExpression';
    operator: '++' | '--';
    argument: Expression;
    prefix: boolean;
}

Unary Expression

interface UnaryExpression {
    type: 'UnaryExpression';
    operator: '+' | '-' | '~' | '!' | 'delete' | 'void' | 'typeof';
    argument: Expression;
    prefix: true;
}

Binary Expression

interface BinaryExpression {
    type: 'BinaryExpression';
    operator: 'instanceof' | 'in' | '+' | '-' | '*' | '/' | '%' | '**' |
        '|' | '^' | '&' | '==' | '!=' | '===' | '!==' |
        '<' | '>' | '<=' | '<<' | '>>' | '>>>';
    left: Expression;
    right: Expression;
}

Logical Expression

interface LogicalExpression {
    type: 'LogicalExpression';
    operator: '||' | '&&';
    left: Expression;
    right: Expression;
}

Conditional Expression

interface ConditionalExpression {
    type: 'ConditionalExpression';
    test: Expression;
    consequent: Statement;
    alternate?: Statement;
}

Yield Expression

interface YieldExpression {
    type: 'YieldExpression';
    argument: Expression | null;
    delegate: boolean;
}

Assignment Expression

interface AssignmentExpression {
    type: 'AssignmentExpression';
    operator: '=' | '*=' | '**=' | '/=' | '%=' | '+=' | '-=' |
        '<<=' | '>>=' | '>>>=' | '&=' | '^=' | '|=';
    left: Expression;
    right: Expression;
}

Sequence Expression

interface SequenceExpression {
    type: 'SequenceExpression';
    expressions: Expression[];
}