How to get current value of Angular Material slide

Question

My question is different to Get mdslider value in angular 2? in that I needed to pass the value of the slider to the component, not just use a local variable; but also in respect of Angular Material having changed so that the slider now requires an $event object to be passed to the component function.

I have an Angular Material slider component in Angular 4:

HTML

<mat-slider min="430" max="500" step="10" value="450" (input)="pitch($event)"></mat-slider>

TS

import { Component, OnInit } from '@angular/core';
import { Inject, Injectable } from '@angular/core';
import { MatSlider } from '@angular/material';
import { AudioContext } from 'angular-audio-context';

@Component({
  selector: 'pitch-slider',
  templateUrl: './pitch-slider.component.html',
  styleUrls: ['./pitch-slider.component.css']
})


export class PitchSliderComponent implements OnInit {



  constructor(private _audioContext: AudioContext) { }

  ngOnInit() {
  }

}

I am quite new to Angular and I'm having trouble getting the current value of the slider. It doesn't seem to work with $event object?

Answer 1

With (input) event when you click outside of mat-slider, it still fired this event.

I changed it to (change) event.

This is my way to display value of mat-slider, I share for whom concern.

TS file

export class SliderOverviewExample {
  gridsize: number = 30;
  updateSetting(event) {
    this.gridsize = event.value;
  }
}

HTML file

<div>
    <span>Grid Size (px): </span><b class="gridSizeValue">{{gridsize.value}}</b>
</div>
<mat-slider #gridsize (change)="updateSetting($event)" 
      step="5" min="10" max="100" [value]="gridsize"></mat-slider>

Demo https://stackblitz.com/edit/angular-display-mat-slider-value?file=app/slider-overview-example.html

Answer 2

I was confused about the $event object - I needed to ref it with just event in the component.ts:

HTML

<h2>freq.</h2>
  <button class="btn btn-primary" (click)="play()">Play</button>
  <mat-slider min="430" max="500" step="10" #matslider (input)="pitch($event)"></mat-slider>

      <div>
        {{ matslider.value }}
      </div>

TS

import { Component, OnInit } from '@angular/core';
import { Inject, Injectable } from '@angular/core';
import { MatSlider } from '@angular/material';
import { AudioContext } from 'angular-audio-context';


@Component({
  selector: 'pitch-slider',
  templateUrl: './pitch-slider.component.html',
  styleUrls: ['./pitch-slider.component.css']
})


export class PitchSliderComponent implements OnInit {
  value: 450;

  constructor(private _audioContext: AudioContext) { }

  ngOnInit() {
  }

  pitch(event: any) {
  console.log(event.value);
}

  play() {
    console.log("play clicked!");
    var frequency = this.value;
    var volume = 0.2;
    var oscillator = this._audioContext.createOscillator();
    var gainNode = this._audioContext.createGain();

    oscillator.connect(gainNode);
    gainNode.connect(this._audioContext.destination);

    gainNode.gain.value = volume;
    oscillator.frequency.value = frequency;

    oscillator.start();

    setTimeout(
      function(){
        oscillator.stop();
      }, 500
    );
  }

}