Function transformThen

test/fixtures/snapshot/typescript.js:151745–151765

* @param hasContinuation Whether another `then`, `catch`, or `finally` continuation follows this continuation. * @param continuationArgName The argument name for the continuation that follows this call.

(node, onFulfilled, onRejected, transformer, hasContinuation, continuationArgName)

         * @param continuationArgName The argument name for the continuation that follows this call.
         */
        function transformThen(node, onFulfilled, onRejected, transformer, hasContinuation, continuationArgName) {
            if (!onFulfilled || isNullOrUndefined(transformer, onFulfilled)) {
                // If we don't have an `onfulfilled` callback, try treating this as a `.catch`.
                return transformCatch(node, onRejected, transformer, hasContinuation, continuationArgName);
            }
            // We don't currently support transforming a `.then` with both onfulfilled and onrejected handlers, per GH#38152.
            if (onRejected && !isNullOrUndefined(transformer, onRejected)) {
                return silentFail();
            }
            var inputArgName = getArgBindingName(onFulfilled, transformer);
            // Transform the left-hand-side of `.then` into an array of inlined statements. We pass `true` for hasContinuation as `node` is the outer continuation.
            var inlinedLeftHandSide = transformExpression(node.expression.expression, node.expression.expression, transformer, /*hasContinuation*/ true, inputArgName);
            if (hasFailed())
                return silentFail(); // shortcut out of more work
            // Transform the callback argument into an array of inlined statements. We pass whether we have an outer continuation here
            // as that indicates whether `return` is valid.
            var inlinedCallback = transformCallbackArgument(onFulfilled, hasContinuation, continuationArgName, inputArgName, node, transformer);
            if (hasFailed())
                return silentFail(); // shortcut out of more work
            return ts.concatenate(inlinedLeftHandSide, inlinedCallback);
        }
        /**
         * Transforms the 'x' part of `x.then(...)`, or the 'y()' part of `y().catch(...)`, where 'x' and 'y()' are Promises.
         */