Vue.js: Set checkboxes checked if statement is true

A possible solution

<input type="checkbox" 
       :checked="job.xmlOnline && job.xmlOnline.includes('stepstone')"
       @change="onChange('stepstone', $event)"> Stepstone
<input type="checkbox" 
       :checked="job.xmlOnline && job.xmlOnline.includes('karriere')"
       @change="onChange('karriere', $event)"> Karriere

And the onChange method

methods:{
  onChange(value, $event){
    if (!this.job.xmlOnline)
      this.job.xmlOnline = []

    const index = this.job.xmlOnline.findIndex(v => v == value) 
    const checked = $event.target.checked

    if (checked && index < 0)
      this.job.xmlOnline.push(value)
    if (!checked && index >= 0)
      this.job.xmlOnline.splice(index, 1)
  }
}

Example.

You can just bind it to a literal as

:true-value="1" 

and it will work as expected.