Where Art Thou-freecodecamp algorithm topics

Where Art Thou

1. Requirements

• Write a function that iterates through an array of objects (the first parameter) and returns an array of all objects that contain matching property-value pairs (the second argument).
• If the returned array contains property-value pairs for the source object, then each property-value pair of this object must exist in the collection object.

2. Ideas

• Remove the property of source with Object.keys (source)
• Use Object.keys () to iterate through the properties of the collection all child elements in the for loop, set the mark tag variable, and initially true in a layer loop.
• Mark becomes false when encountering a collection child element without a Sourse attribute in the For loop or when two corresponding property values are not equal
• A layer of loops finally, if Mark is true, push the corresponding collection child element to the result array

3. Code

function where(collection, source) {var arr = [];var arrj = Object.keys(source);for(var i = 0; i<collection.length; i++){    var arri = Object.keys(collection[i]);    var mark = true;    for (var j = 0; j < arrj.length; j++){    if (arri.indexOf(arrj[j]) === -1 ||  collection[i][arrj[j]] !== source[arrj[j]]) {        mark =false;    }    }    if (mark){    arr.push(collection[i]);    }}// What‘s in a name?return arr;}where([{ first: "Romeo", last: "Montague" }, { first: "Mercutio", last: null }, { first: "Tybalt", last: "Capulet" }], { last: "Capulet" });

4. RELATED LINKS

• Https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Object/keys

Where Art Thou-freecodecamp algorithm topics