such.ns-state
Manipulate, in a stateful way, a key-value store that belongs to a particular namespace.
Throughout this documentation, f is any callable. It must not have side effects. k is a value (of any type) that indexes the key-value store.
Values in the store can be treated as single entities or as stacks.
All state-changing operations end in `“!”. They are atomic. Except where explicitly noted, their return value is undefined.
alter!
(alter! k f & args)Replace the value of the store at k with the value of (apply f <current-val> args).
(nss/alter! :counter + 2)
count
(count k)The value of the store at k must be a stack. Returns the number of elements. A never-created (or destroyed) stack has zero elements.
dissoc!
(dissoc! & ks)(dissoc!)In the no-argument versions, delete all keys from the store. In the N-argument version, delete each of the keys.
empty?
(empty? k)The value of the store at k must be a stack. Returns true iff the stack has no elements. A never-created (or destroyed) stack has zero elements.
flattened-history
(flattened-history k)The value of the store at k must be a stack. Each element must be a sequential collection. The result is a vector of flatten applied to the history.
(nss/push! :s [1 2)
(nss/push! :s [])
(nss/push! :s [3])
(nss/flattened-history :s) => [1 2 3]
get
(get k)(get k default)Return the value of the store at k or the default if there is no value. If no default value, return nil.
history
(history k)The value of the store at k must be a stack. The elements are returned in the order they were pushed. (Thus, top is the final element.) The return value is specifically a vector.
(nss/push! :s 1)
(nss/push! :s 2)
(nss/history :s) => [1 2]
pop!
(pop! k)Change the stack at k to remove its top. Throws an Exception if the stack is empty or does not exist.
push!
(push! k v)Change the stack at k to have v as its top element. The stack need not be created before the first push.
top
(top k)Returns the element of the stack at k that was most recently pushed. Throws an Exception if the stack is empty or does not exist.
(nss/push! :s 1)
(nss/push! :s 2)
(nss/pop! :s)
(nss/top :s) => 1