How to calculate function return value in vue

Vue function return value can be calculated in three ways: Calculated property: Define a function that calculates a value based on component data. Its return value will be cached and will only be recalculated when the dependent data changes. Method: Define a function that recalculates the value each time it is called. Template inline calculation: Use JavaScript expressions to perform calculations directly in the template.

Calculation of function return value in Vue

Function in Vue can return any JavaScript expression result, including calculation value.

Computed Properties

The most common way is to use computed properties. A computed property is a function that returns a value calculated based on component data. The return value of a computed property is cached, which means it is only recalculated when the dependent data changes. For example:

computed: {
  total() {
    return this.price * this.quantity;
  }
}

Method

Function can also be used as a method to return a calculated value. Methods are not cached, so they are recalculated on each call. For example:

methods: {
  calculateTotal() {
    return this.price * this.quantity;
  }
}

Inline calculation in template

You can also use JavaScript expressions to perform calculations directly in the template. For example:

<template>
  <div>{{ price * quantity }}</div>
</template>

Notes

You need to pay attention to the following points:

• The return values ​​​​of calculated properties and methods must be responsive of. This means they should be updated using Vue's reactive API such as this.$set or Vue.set.
• When using JavaScript expressions in templates, be sure to enclose the expression in double curly braces using the {{}} syntax.
• Avoid performing complex calculations or calling external functions in computed properties or methods. This may impact performance and maintainability.

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