update: state, event, condition, data.event.types

packages/vitex/index.ts

@@ -0,0 +1,24 @@
+export type RNG = (max?: number, min?: number) => number
+export function random(max: number, min: number = 0, rng?: RNG): number {
+    if (rng) return rng(max, min)
+    return Math.floor(Math.random() * (max - min + 1)) + min
+}
+export function pick<T>(items: T[], rng?: RNG) {
+    if (items.length === 0) return null
+    return items[random(items.length - 1, 0, rng)]
+}
+export type WeightItem<T> = [T, number]
+export function pickWeight<T>(items: WeightItem<T>[], rng?: RNG) {
+    if (items.length === 0) return null
+    const totalWeight = items.reduce((sum, [, weight]) => sum + weight, 0)
+    let mark = random(totalWeight - 1, 0, rng)
+    for (const [item, weight] of items) {
+        if (mark < weight) return item
+        mark -= weight
+    }
+    return null
+}
+
+export function sum(arr: number[]) {
+    return arr.reduce((sum, v) => sum + v, 0)
+}