Implementation method of object array deep property access function in Vue document

Vue is a popular JavaScript framework for developing single page applications (SPA). Vue provides many convenient methods for working with data. When we use Vue to deal with object arrays, we often need to access deep properties nested in the object array. This article will introduce how to use the deep property access functions provided in the Vue documentation to handle nested properties in an object array.

In the Vue documentation, there is a method called $set, which allows us to dynamically add properties to the object. If you want to dynamically add a nested property to a new object, you can use the following code:

let data = {
    myObject: {}
}
Vue.set(data.myObject, 'myProperty', 'myValue');

In order to access the properties in the nested object, you can use the following code:

let myObject = {
    myPropertyA: {
        myPropertyB: {
            myPropertyC: 'myValue'
        }
    }
};
let myValue = myObject['myPropertyA']['myPropertyB']['myPropertyC'];

But when nested This method can become very tedious when the layers are deep. In order to make the code more streamlined and readable, Vue provides some utility functions. Here's how these functions are implemented:

First, we need to write a recursive function to access the nested properties. This function will take two parameters: an object and a property path. As shown below:

function getNestedProperty(obj, propertyPath) {
    if (typeof propertyPath === 'string') {
        propertyPath = propertyPath.split('.');
    }
    if (propertyPath.length === 1) {
        return obj[propertyPath[0]];
    } else {
        let nextObj = obj[propertyPath[0]];
        let nextPath = propertyPath.slice(1);
        return getNestedProperty(nextObj, nextPath);
    }
}

In this function, first check whether the attribute path is a string. If it's a string, split it into an array. Next, if the attribute path array has only one element, the attribute value in the object is returned. Otherwise, get the property value of the first element in that object and use a recursive call to the function to get the property in the next nested object. The recursive exit is to return the value of the attribute when the attribute path array cannot be split further.

Now, we need to write a setter method to set the nested property. This method will take three parameters: an object, a property path, and a new value. As shown below:

function setNestedProperty(obj, propertyPath, value) {
    if (typeof propertyPath === 'string') {
        propertyPath = propertyPath.split('.');
    }
    if (propertyPath.length === 1) {
        Vue.set(obj, propertyPath[0], value);
    } else {
        let nextObj = obj[propertyPath[0]];
        if (!nextObj) {
            Vue.set(obj, propertyPath[0], {});
            nextObj = obj[propertyPath[0]];
        }
        let nextPath = propertyPath.slice(1);
        setNestedProperty(nextObj, nextPath, value);
    }
}

In this method, first check whether the attribute path is a string. If it's a string, split it into an array. If the property path array has only one element, use Vue's $set method to set the property of the object to a new value. Otherwise, get the attribute value of the first element in this object and use the recursive add function to get the attribute in the next nested object. The recursive exit is to use Vue's $set method to set the value of the property when the property path array cannot be split any further.

Use these functions to access and set nested properties in an object array. The following is an example:

let myData = {
    myArray: [
        {
            myObject: {
                myPropertyA: {
                    myPropertyB: {
                        myPropertyC: 'myValue'
                    }
                }
            }
        }
    ]
};
let myValue = getNestedProperty(myData, 'myArray.0.myObject.myPropertyA.myPropertyB.myPropertyC'); // myValue = 'myValue'

setNestedProperty(myData, 'myArray.0.myObject.myPropertyA.myPropertyB.myPropertyC', 'newValue');

In this article, we introduced the deep property access functions in the Vue document and provided two implementation methods: getNestedProperty and setNestedProperty. These functions make it easier to access and set nested properties in an array of objects, without making the code very verbose.

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