Add stepper.ts

frontend/models/stepper.ts

@@ -0,0 +1,48 @@
+export class StepCounter {
+  private step: number
+
+  constructor(
+    private readonly minStep: number = 1,
+    private readonly maxStep: number = 10
+  ) {
+    this.step = 1
+  }
+
+  static valueOf(
+    minStep: number = 1, maxStep: number = 10
+  ): StepCounter {
+    return new StepCounter(minStep, maxStep)
+  }
+
+  get count(): number {
+    return this.step
+  }
+
+  set count(val: number) {
+    this.step = val
+  }
+
+  next(): void {
+    this.step = Math.min(this.step + 1, this.maxStep)
+  }
+
+  prev(): void {
+    this.step = Math.max(this.step - 1, this.minStep)
+  }
+
+  hasNext(): boolean {
+    return this.step !== this.maxStep
+  }
+
+  hasPrev(): boolean {
+    return this.step !== this.minStep
+  }
+
+  isFirst(): boolean {
+    return this.step === this.minStep
+  }
+
+  isLast(): boolean {
+    return this.step === this.maxStep
+  }
+}