Vue: binding with v-model in custom checkbox component doesn't work
When you do
this.$emit('input', e.target.value);it works like
myCheckBoxModel = e.target.valueSo it just assigns the value of the last checkbox you clicked to myCheckBoxModel.If you want to keep all checked items in myCheckBoxModel, you need to do the following:
- add
valueproperty toui-checkboxcomponent to have access to the current value ofmyCheckBoxModel.Valueis default property name for this goal (see vue guide). - in your
onChangemethod copy the current value to the variable, because it's not good to mutatevalueproperty directly - if your checkbox is checked, push the correspondent value to the array. If the checkbox is not checked, delete to correspondent value from the array
- emit
inputevent with the resulting array as value
Vue.component('ui-checkbox', { props: { label: { type: String, required: true, }, index: { type: Number }, inputValue: { type: String }, value: { type: Array } }, methods: { onChange(e) { let currentValue = [...this.value] if (e.target.checked) { currentValue.push(e.target.value) } else { currentValue = currentValue.filter(item => item !== e.target.value) } this.$emit('input', currentValue); }, }, template: `<div> <input :id="index" type="checkbox" :value="inputValue" @change="onChange" /> <label :for="index"> {{ label }} </label> </div>`, }) new Vue({ el: "#app", data: { checkOptions: [ { label: 'Option 1', value: 'value of option 1', }, { label: 'Option 2', value: 'value of option 2', }, { label: 'Option 3', value: 'value of option 3', }, { label: 'Option 4', value: 'value of option 4', }, ], myCheckBoxModel: [] } })<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script> <div id="app"> checked Checkboxes: <span v-for="item in myCheckBoxModel"> {{ item }}; </span> <ui-checkbox v-for="(option, index) in checkOptions" v-model="myCheckBoxModel" :key="index" :index="index" :input-value="option.value" :label="option.label" /> </div>I don't know if you need to set checkbox state programmatically, i.e. when you change myCheckBoxModel the state of checkboxes changes correspondently. If you do, you need to watch value property in your ui-checkbox component: set the state of the check box in dependance of if its value is in value array. Do the same also in created hook if you want to initialize the state of checkboxes by myChexkboxModel
The solution presented by @Lana is just too complicated. The onChange method is not needed at all - what you want is to use build-in power of v-model. See below...
Vue.component('ui-checkbox', { props: { label: { type: String, required: true, }, index: { type: Number }, inputValue: { type: String }, value: { type: Array } }, computed: { model: { get() { return this.value }, set(value) { this.$emit('input', value) } }, }, template: `<div> <input :id="index" type="checkbox" :value="inputValue" v-model="model" /> <label :for="index"> {{ label }} </label> </div>`,})new Vue({ el: "#app", data: { checkOptions: [{ label: 'Option 1', value: 'value of option 1', }, { label: 'Option 2', value: 'value of option 2', }, { label: 'Option 3', value: 'value of option 3', }, { label: 'Option 4', value: 'value of option 4', }, ], myCheckBoxModel: [] }})<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/2.5.17/vue.js"></script><div id="app"> model: {{ myCheckBoxModel }} <ui-checkbox v-for="(option, index) in checkOptions" v-model="myCheckBoxModel" :key="index" :index="index" :input-value="option.value" :label="option.label" /></div>