Answers for "vue props"

vue js default prop

props: {
  name: {
    type: String,
    default: 'John Doe'
  }
}

vue prop string or number

props: {
        users_count: {
            type: [Number, String],
            required: true
        }
    },

props vue js

Vue.component('my-component', {
  props: {
    // Basic type check (`null` and `undefined` values will pass any type validation)
    propA: Number,
    // Multiple possible types
    propB: [String, Number],
    // Required string
    propC: {
      type: String,
      required: true
    },
    // Number with a default value
    propD: {
      type: Number,
      default: 100
    },
    // Object with a default value
    propE: {
      type: Object,
      // Object or array defaults must be returned from
      // a factory function
      default: function () {
        return { message: 'hello' }
      }
    },
    // Custom validator function
    propF: {
      validator: function (value) {
        // The value must match one of these strings
        return ['success', 'warning', 'danger'].indexOf(value) !== -1
      }
    }
  }
})

how to access both child event param and parent param in vue

<template>
    <ul>
        <product v-for="product in products"
                 :product="product"
                 @add="addToChart" />
    </ul>
</template>

<script>
const Product = {
    props: ["product"],
    render(h) {
        return h("li", { on: { click: this.click } }, this.product);
    },
    methods: {
        click() {
            this.$emit("add", { product: this.product, quantity: 42 });
        }
    }
};

export default {
    data() {
        return {
            products: ["Foo", "Bar"]
        };
    },
    components: {
        Product
    },
    methods: {
        addToChart({ product, quantity }) {
            console.log(product, quantity);
        }
    }
}
</script>

vue passing props

<!-- Dynamically assign the value of a variable -->
<blog-post v-bind:title="post.title"></blog-post>

<!-- Dynamically assign the value of a complex expression -->
<blog-post
  v-bind:title="post.title + ' by ' + post.author.name"
></blog-post>