[Vuejs]-Save input and give output in VueJs

You have to duplicate your object, one containing the current state the other one the new state. When pushing the button, you update the current state.

export default {
  name: "Measurements",
  created() {
    this.newState = JSON.parse(JSON.stringify(this.currentState));
  },
  data () {
    return {
      currentState: { },
      newState: {}
    };
  },
  methods: {
    addItems() {
      this.currentState= JSON.parse(JSON.stringify(this.newState));
    }
  }
};

Just add a new variable to determine the visible/hidden state of your input. You can do so by adding a v-if to your html element and adjusting your addItems method just like that.

  data: () => {
    return {
       ...
       showHeight: false,
       ...
    };
  },
  methods: {
      addItems() {
        this.showHeight = true;
      }
  }