Function bindOptionalChain

test/fixtures/snapshot/typescript.js:46123–46145

(node, trueTarget, falseTarget)

            }
        }
        function bindOptionalChain(node, trueTarget, falseTarget) {
            // For an optional chain, we emulate the behavior of a logical expression:
            //
            // a?.b         -> a && a.b
            // a?.b.c       -> a && a.b.c
            // a?.b?.c      -> a && a.b && a.b.c
            // a?.[x = 1]   -> a && a[x = 1]
            //
            // To do this we descend through the chain until we reach the root of a chain (the expression with a `?.`)
            // and build it's CFA graph as if it were the first condition (`a && ...`). Then we bind the rest
            // of the node as part of the "true" branch, and continue to do so as we ascend back up to the outermost
            // chain node. We then treat the entire node as the right side of the expression.
            var preChainLabel = ts.isOptionalChainRoot(node) ? createBranchLabel() : undefined;
            bindOptionalExpression(node.expression, preChainLabel || trueTarget, falseTarget);
            if (preChainLabel) {
                currentFlow = finishFlowLabel(preChainLabel);
            }
            doWithConditionalBranches(bindOptionalChainRest, node, trueTarget, falseTarget);
            if (ts.isOutermostOptionalChain(node)) {
                addAntecedent(trueTarget, createFlowCondition(32 /* FlowFlags.TrueCondition */, currentFlow, node));
                addAntecedent(falseTarget, createFlowCondition(64 /* FlowFlags.FalseCondition */, currentFlow, node));
            }
        }
        function bindOptionalChainFlow(node) {
            if (isTopLevelLogicalExpression(node)) {
                var postExpressionLabel = createBranchLabel();