Function buildElementTreeItem

src/elementTree.js:50–148

* @param {Object} ast * @param {{tokens: Array, token: Object, pos: Number}} state * @returns {Element}

(ast: Object, state: ElementTreeItemState)

 * @returns {Element}
 */
function buildElementTreeItem(ast: Object, state: ElementTreeItemState): ?Element {
    let elementType = ast.type;
    let childProps = visitorKeys[elementType];

    // Skip first `Identifier` for ({ test = 1 } = {})
    // since it is already used in `AssignmentPattern`
    // Need to fix this one day (See https://github.com/babel/babylon/issues/49)
    if (
        ast.type === 'ObjectProperty' &&
        ast.value.type === 'AssignmentPattern'
    ) {
        delete ast.key;
    }

    if (!childProps) {
        let error = new SyntaxError(`Cannot iterate using ${elementType}`);
        error.loc = ast.loc.start;
        throw error;
    }

    let childElements = [];
    for (let i = 0; i < childProps.length; i++) {
        let childAst = ast[childProps[i]];

        if (!childAst) {
            continue;
        }

        if (Array.isArray(childAst)) {
            for (let j = 0; j < childAst.length; j++) {
                if (childAst[j] === null) {
                    continue;
                }

                childElements[childElements.length] = childAst[j];
            }
        } else {
            childElements[childElements.length] = childAst;
        }
    }

    childElements.sort((ast1, ast2) => {
        return ast1.start < ast2.start ? -1 : (ast1.start > ast2.start ? 1 : 0);
    });

    let NodeClass = elementIndex[elementType];

    if (!NodeClass) {
        throw new Error(`Cannot create ${elementType} instance`);
    }

    let children = [];
    let childElementIndex = 0;
    let childElement = childElements[0];
    let end = ast.end;

    do {
        if (childElement && state.token.start === childElement.start) {