demo/typescript.js
function contextualTypeHasIndexSignature(type, kind) {
            return !!(type.flags & 16384 /* Union */ ? ts.forEach(type.types, function (t) { return getIndexTypeOfStructuredType(t, kind); }) : getIndexTypeOfStructuredType(type, kind));
        }
function contextualTypeHasIndexSignature(type, kind) {
            return !!(type.flags & 16384 /* Union */ ? ts.forEach(type.types, function (t) { return getIndexTypeOfStructuredType(t, kind); }) : getIndexTypeOfStructuredType(type, kind));
        }
Return true if the given contextual type provides an index signature of the given kind