I can't figure out why this.sendDrag('started') returns this error:

"Uncaught TypeError: this.sendDrag is not a function"

  methods: {
    sendDrag (val) {
      console.log(val)
    }
[...]



    mounted () {
        this.$nextTick(() => {
          this.$refs.flickity.on('dragStart', function () {
            this.stageDragging = true
            this.sendDrag('started')
          })

What causes the error and how to fix it?

I can't figure out why this.sendDrag('started') returns this error:

"Uncaught TypeError: this.sendDrag is not a function"

  methods: {
    sendDrag (val) {
      console.log(val)
    }
[...]



    mounted () {
        this.$nextTick(() => {
          this.$refs.flickity.on('dragStart', function () {
            this.stageDragging = true
            this.sendDrag('started')
          })

What causes the error and how to fix it?

• javascript
• vue.js
• vuejs2

• i think it is because this scoping. U could use arrow function ... or use self helper. I mean arrow function insted of function() – curious lad Commented Apr 30, 2019 at 20:04
• I don't understand what you mean. Can you please provide an example? – Tom Commented Apr 30, 2019 at 20:28
• 1 Here is the solution to your problem: stackoverflow./a/55836450/10251861 – sml-sgr Commented Apr 30, 2019 at 20:47

1 Answer 1

You need to capture the value of this in the closure because you are calling it from a function that has a different this.

If you used the arrow-lambda notation ()=>{} instead of function() it would capture this for you automatically. And that is the real difference between the two notations.

mounted () {
        this.$nextTick(() => {
          const that = this;
          this.$refs.flickity.on('dragStart', function () {
            that.stageDragging = true
            that.sendDrag('started')
          })