Function flattenArrayBindingOrAssignmentPattern

test/fixtures/snapshot/typescript.js:91294–91356

* Flattens an ArrayBindingOrAssignmentPattern into zero or more bindings or assignments. * * @param flattenContext Options used to control flattening. * @param parent The parent element of the pattern. * @param pattern The ArrayBindingOrAssignmentPattern to flatten. * @param

(flattenContext, parent, pattern, value, location)

     * @param location The location to use for source maps and comments.
     */
    function flattenArrayBindingOrAssignmentPattern(flattenContext, parent, pattern, value, location) {
        var elements = ts.getElementsOfBindingOrAssignmentPattern(pattern);
        var numElements = elements.length;
        if (flattenContext.level < 1 /* FlattenLevel.ObjectRest */ && flattenContext.downlevelIteration) {
            // Read the elements of the iterable into an array
            value = ensureIdentifier(flattenContext, ts.setTextRange(flattenContext.context.getEmitHelperFactory().createReadHelper(value, numElements > 0 && ts.getRestIndicatorOfBindingOrAssignmentElement(elements[numElements - 1])
                ? undefined
                : numElements), location), 
            /*reuseIdentifierExpressions*/ false, location);
        }
        else if (numElements !== 1 && (flattenContext.level < 1 /* FlattenLevel.ObjectRest */ || numElements === 0)
            || ts.every(elements, ts.isOmittedExpression)) {
            // For anything other than a single-element destructuring we need to generate a temporary
            // to ensure value is evaluated exactly once. Additionally, if we have zero elements
            // we need to emit *something* to ensure that in case a 'var' keyword was already emitted,
            // so in that case, we'll intentionally create that temporary.
            // Or all the elements of the binding pattern are omitted expression such as "var [,] = [1,2]",
            // then we will create temporary variable.
            var reuseIdentifierExpressions = !ts.isDeclarationBindingElement(parent) || numElements !== 0;
            value = ensureIdentifier(flattenContext, value, reuseIdentifierExpressions, location);
        }
        var bindingElements;
        var restContainingElements;
        for (var i = 0; i < numElements; i++) {
            var element = elements[i];
            if (flattenContext.level >= 1 /* FlattenLevel.ObjectRest */) {
                // If an array pattern contains an ObjectRest, we must cache the result so that we
                // can perform the ObjectRest destructuring in a different declaration
                if (element.transformFlags & 32768 /* TransformFlags.ContainsObjectRestOrSpread */ || flattenContext.hasTransformedPriorElement && !isSimpleBindingOrAssignmentElement(element)) {
                    flattenContext.hasTransformedPriorElement = true;
                    var temp = flattenContext.context.factory.createTempVariable(/*recordTempVariable*/ undefined);
                    if (flattenContext.hoistTempVariables) {
                        flattenContext.context.hoistVariableDeclaration(temp);
                    }
                    restContainingElements = ts.append(restContainingElements, [temp, element]);
                    bindingElements = ts.append(bindingElements, flattenContext.createArrayBindingOrAssignmentElement(temp));
                }
                else {
                    bindingElements = ts.append(bindingElements, element);
                }
            }
            else if (ts.isOmittedExpression(element)) {
                continue;
            }
            else if (!ts.getRestIndicatorOfBindingOrAssignmentElement(element)) {
                var rhsValue = flattenContext.context.factory.createElementAccessExpression(value, i);
                flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, /*location*/ element);
            }
            else if (i === numElements - 1) {
                var rhsValue = flattenContext.context.factory.createArraySliceCall(value, i);
                flattenBindingOrAssignmentElement(flattenContext, element, rhsValue, /*location*/ element);
            }
        }
        if (bindingElements) {
            flattenContext.emitBindingOrAssignment(flattenContext.createArrayBindingOrAssignmentPattern(bindingElements), value, location, pattern);
        }
        if (restContainingElements) {
            for (var _i = 0, restContainingElements_1 = restContainingElements; _i < restContainingElements_1.length; _i++) {