254       id: options.id || uniqueId(),  property in pjax.state
302       id: uniqueId(),  property in pjax.state
325       cachePush(pjax.state.id, context.clone().contents())
394       var direction, contents = cacheMapping[state.id]
399         direction = pjax.state.id < state.id ? 'forward' : 'back'
403         cachePop(direction, pjax.state.id, container.clone().contents())
413         id: state.id,  property in container.trigger
705 function cachePush(id, value) {  argument
706   cacheMapping[id] = value
707   cacheBackStack.push(id)
728 function cachePop(direction, id, value) {  argument
730   cacheMapping[id] = value
740   pushStack.push(id)
741   if (id = popStack.pop())
742     delete cacheMapping[id]