Tish - Native Performance, Familiar Syntax

Overview

Map is a collection of key → value entries that remembers insertion order and works identically across every Tish backend — the interpreter, the bytecode VM, and native (AOT) compiled binaries. Keys are compared with SameValueZero equality: NaN matches NaN, +0/-0 are the same, primitives compare by value, and objects compare by identity. Any value may be a key.

let m = new Map([["a", 1], ["b", 2]])
m.get("a")   // 1
m.size       // 2

Constructor

Form	Result
`new Map()`	An empty map.
`new Map(iterable)`	A map seeded from an array of `[key, value]` pairs.

Properties & methods

Member	Description
`.size`	Number of entries (a computed property).
`.set(key, value)`	Insert or update `key`.
`.get(key)`	The value for `key`, or `undefined`.
`.has(key)`	`true` if `key` is present.
`.delete(key)`	Remove `key`; returns `true` if it was present.
`.clear()`	Remove all entries.
`.keys()`	An iterator over the keys in insertion order.
`.values()`	An iterator over the values in insertion order.
`.entries()`	An iterator over `[key, value]` pairs.

Iteration

.keys(), .values(), and .entries() return real iterators — objects with a .next() method that yields { value, done } — so they work both directly and in for...of / spread, just like JavaScript:

let m = new Map([["a", 1], ["b", 2], ["c", 3]])
 
let total = 0
for (let v of m.values()) {
  total = total + v
}
total   // 6
 
for (let pair of m.entries()) {
  // pair[0] is the key, pair[1] is the value
}
 
// Iterator API + spread
let it = m.keys()
it.next()              // { value: "a", done: false }
[...m.values()]        // [1, 2, 3]

The iterator snapshots the map when it is created; mutating the map mid-iteration is not reflected (a live iterator is a follow-up).

Examples

let counts = new Map()
counts.set("apple", 1)
counts.set("pear", 2)
counts.set("apple", 5)   // updates the existing key
counts.size              // 2
counts.get("apple")      // 5
counts.has("pear")       // true
counts.delete("pear")    // true
counts.size              // 1
 
// Any value works as a key.
let byId = new Map()
byId.set(1, "one")
byId.set(2, "two")
byId.get(1)              // "one"

Compatibility notes (v1)

forEach is not available yet, and .set() does not return the map (no method chaining). Iterate with for...of over .entries() / .keys() / .values().
Direct for (entry of map) and [...map] are not wired yet — use .entries() / .keys() / .values(), which return arrays.
console.log(map) prints the underlying object rather than Map(n) {…}.