jspm_packages/system-polyfills.src.js
function Fold(f, z, c, to) {
			this.f = f; this.z = z; this.c = c; this.to = to;
			this.resolver = failIfRejected;
			this.receiver = this;
		}
function Fold(f, z, c, to) {
			this.f = f; this.z = z; this.c = c; this.to = to;
			this.resolver = failIfRejected;
			this.receiver = this;
		}
function Fold ( f , z , c , to ) { this . f = f ; this . z = z ; this . c = c ; this . to = to ; this . resolver = failIfRejected ; this . receiver = this ; }
Fold a handler value with z
@constructor
Fold a handler value with z