Function getUnionSignatures

test/fixtures/snapshot/typescript.js:58100–58158

(signatureLists)

        // parameters and may differ in return types. When signatures differ in return types, the resulting return
        // type is the union of the constituent return types.
        function getUnionSignatures(signatureLists) {
            var result;
            var indexWithLengthOverOne;
            for (var i = 0; i < signatureLists.length; i++) {
                if (signatureLists[i].length === 0)
                    return ts.emptyArray;
                if (signatureLists[i].length > 1) {
                    indexWithLengthOverOne = indexWithLengthOverOne === undefined ? i : -1; // -1 is a signal there are multiple overload sets
                }
                for (var _i = 0, _a = signatureLists[i]; _i < _a.length; _i++) {
                    var signature = _a[_i];
                    // Only process signatures with parameter lists that aren't already in the result list
                    if (!result || !findMatchingSignature(result, signature, /*partialMatch*/ false, /*ignoreThisTypes*/ false, /*ignoreReturnTypes*/ true)) {
                        var unionSignatures = findMatchingSignatures(signatureLists, signature, i);
                        if (unionSignatures) {
                            var s = signature;
                            // Union the result types when more than one signature matches
                            if (unionSignatures.length > 1) {
                                var thisParameter = signature.thisParameter;
                                var firstThisParameterOfUnionSignatures = ts.forEach(unionSignatures, function (sig) { return sig.thisParameter; });
                                if (firstThisParameterOfUnionSignatures) {
                                    var thisType = getIntersectionType(ts.mapDefined(unionSignatures, function (sig) { return sig.thisParameter && getTypeOfSymbol(sig.thisParameter); }));
                                    thisParameter = createSymbolWithType(firstThisParameterOfUnionSignatures, thisType);
                                }
                                s = createUnionSignature(signature, unionSignatures);
                                s.thisParameter = thisParameter;
                            }
                            (result || (result = [])).push(s);
                        }
                    }
                }
            }
            if (!ts.length(result) && indexWithLengthOverOne !== -1) {
                // No sufficiently similar signature existed to subsume all the other signatures in the union - time to see if we can make a single
                // signature that handles all over them. We only do this when there are overloads in only one constituent.
                // (Overloads are conditional in nature and having overloads in multiple constituents would necessitate making a power set of
                // signatures from the type, whose ordering would be non-obvious)
                var masterList = signatureLists[indexWithLengthOverOne !== undefined ? indexWithLengthOverOne : 0];
                var results = masterList.slice();
                var _loop_10 = function (signatures) {
                    if (signatures !== masterList) {
                        var signature_1 = signatures[0];
                        ts.Debug.assert(!!signature_1, "getUnionSignatures bails early on empty signature lists and should not have empty lists on second pass");
                        results = !!signature_1.typeParameters && ts.some(results, function (s) { return !!s.typeParameters && !compareTypeParametersIdentical(signature_1.typeParameters, s.typeParameters); }) ? undefined : ts.map(results, function (sig) { return combineSignaturesOfUnionMembers(sig, signature_1); });
                        if (!results) {
                            return "break";
                        }
                    }
                };
                for (var _b = 0, signatureLists_1 = signatureLists; _b < signatureLists_1.length; _b++) {
                    var signatures = signatureLists_1[_b];
                    var state_3 = _loop_10(signatures);
                    if (state_3 === "break")
                        break;
                }
                result = results;
            }
            return result || ts.emptyArray;