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JSX extensions to Mozilla AST Format

JSX extends ECMAScript ESTree AST format with the following node types:

JSX Names

JSX Identifier subtype

interface JSXIdentifier <: Identifier {
    type: "JSXIdentifier";

Namespaced names

Property-like namespace syntax (tag names only):

interface JSXMemberExpression <: Expression {
    type: "JSXMemberExpression";
    object: JSXMemberExpression | JSXIdentifier;
    property: JSXIdentifier;

XML-based namespace syntax:

interface JSXNamespacedName <: Expression {
    type: "JSXNamespacedName";
    namespace: JSXIdentifier;
    name: JSXIdentifier;

JSX Expression Container

JSX adds empty "expression" type in order to allow comments in JSX text:

interface JSXEmptyExpression <: Node {
    type: "JSXEmptyExpression";

Any expression used as attribute value or inside JSX text should is wrapped into expression container:

interface JSXExpressionContainer <: Node {
    type: "JSXExpressionContainer";
    expression: Expression | JSXEmptyExpression;

A JSX element uses a special form of an expression container for an iterator child who should be “spread out” inside an element’s children list:

interface JSXSpreadChild <: Node {
    type: "JSXSpreadChild";
    expression: Expression;

JSX Boundary Tags

Any JSX element is bounded by tags — either self-closing or both opening and closing elements:

interface JSXBoundaryElement <: Node {
    name: JSXIdentifier | JSXMemberExpression | JSXNamespacedName;

interface JSXOpeningElement <: JSXBoundaryElement {
    type: "JSXOpeningElement";
    attributes: [ JSXAttribute | JSXSpreadAttribute ];
    selfClosing: boolean;

interface JSXClosingElement <: JSXBoundaryElement {
    type: "JSXClosingElement";

JSX Attributes

Opening element ("tag") may contain attributes:

interface JSXAttribute <: Node {
    type: "JSXAttribute";
    name: JSXIdentifier | JSXNamespacedName;
    value: Literal | JSXExpressionContainer | JSXElement | JSXFragment | null;

interface JSXSpreadAttribute <: SpreadElement {
    type: "JSXSpreadAttribute";

JSX Text

JSX Text node stores a string literal found in JSX element children.

interface JSXText <: Node {
  type: "JSXText";
  value: string;
  raw: string;

JSX Element

JSX element consists of opening element, list of children and optional closing element:

interface JSXElement <: Expression {
    type: "JSXElement";
    openingElement: JSXOpeningElement;
    children: [ JSXText | JSXExpressionContainer | JSXSpreadChild | JSXElement | JSXFragment ];
    closingElement: JSXClosingElement | null;

JSX Fragment

JSX fragment consists of an opening fragment, list of children, and closing fragment:

interface JSXFragment <: Expression {
    type: "JSXFragment";
    openingFragment: JSXOpeningFragment;
    children: [ JSXText | JSXExpressionContainer | JSXSpreadChild | JSXElement | JSXFragment ];
    closingFragment: JSXClosingFragment;
interface JSXOpeningFragment <: Node {
    type: "JSXOpeningFragment";
interface JSXClosingFragment <: Node {
    type: "JSXClosingFragment";

Tools that work with JSX AST


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