What is the best way to combine two arrays containing objects?

Question

What is the best way to combine two arrays containing objects?

I currently have two arrays containing objects:

let employees = [
  { name: 'Jason', job_id: '101' },
  { name: 'Sarah', job_id: '102' },
  { name: 'Jack', job_id: '102' }
]

let jobs = [
  { job_id: '101', position: 'Designer' },
  { job_id: '102', position: 'Developer' }
]

Is there a way for me to merge these arrays using vanilla javascript, as shown below:

let employees = [
  { name: 'Jason', job_id: [job_id: '101', position: 'Designer'] },
  { name: 'Sarah', job_id: [job_id: '102', position: 'Developer'] },
  { name: 'Jack', job_id: [job_id: '102', position: 'Developer'] }
]

The code snippet I have now does work correctly, but if possible, I would prefer not to rely on nested loops.

employees.forEach(employee => {
  for (let index = 0; index < jobs.length; index++) {
    if (employee.job_id == jobs[index].job_id) {
      employee.job_id= jobs[index];
    }
  }
})

javascript arrays

Answer 1

Answer №1

Completing this task is relatively straightforward, so I will provide a simple answer with a live demonstration.

The approach involves iterating through the employees array and constructing objects with the desired structure, then pushing them into a final array.

Each object in the final array will include the following attributes:

name: corresponds to the name in the employees array (for each iteration)
job: for clarity, I will use job instead of job_id as indicated in your expected output. The job attribute is an object that includes
- id: representing the job_id from the employees array
- position: indicating the relevant position from the jobs array

To achieve the above outcome, we will utilize the reduce method to build the final array incrementally.

Furthermore, obtaining the corresponding position from the jobs array based on the job_id from the employees table can be accomplished using the find method which returns the first matching element from the jobs array.

With that explanation in mind, let's proceed with a live demonstration (including instructive comments):

const employees = [{
      name: 'Jason',
      job_id: '101'
    },
    {
      name: 'Sarah',
      job_id: '102'
    },
    {
      name: 'Jack',
      job_id: '102'
    }
  ],
  jobs = [{
      job_id: '101',
      position: 'Designer'
    },
    {
      job_id: '102',
      position: 'Developer'
    }
  ],
  /** 
   * "res" represents the resulting array after performing necessary operations 
   * The "reduce" method traverses the "employees" array to populate the "res" array accordingly
   */
  res = employees.reduce((a, c) => {
    /**
     * a: holds the prior value from the previous iteration - initially set to an empty array "[]" (referenced in the 3rd argument passed to the "reduce" method)
     * c: denotes the current element from the "employees" array for each iteration
     */

    /** appends an object adhering to the intended structure to the final array */
    a.push({
      name: c.name,
      job: {
        id: c.job_id,
        /** 
         * Locate the respective "position" based on the "job_id" of the current element within the "employees" array 
         * el: references the element from the "jobs" array during each iteration of the "find" method
         * the condition checks for an element where "job_id" matches the current element's "job_id," subsequently returning the associated "position"
         * once the "position" is found, it is assigned to the object being constructed
         */
        position: jobs.find(el => el.job_id == c.job_id).position
      }
    });
    /** return the array to enable the next iteration of "reduce" to proceed */
    return a;
  }, []);

/** display the result */
console.log(res);

While the presented demo is one way to accomplish the task, there are undoubtedly alternative ES6 methods available for crafting objects. For simplicity's sake, I have opted for straightforward and comprehensible approaches without utilizing intricate techniques.

For further insight, explore the reduce method documentation on MDN.

Delve into details about the find method via MDN resources.

Answer 2

Completing this task is relatively straightforward, so I will provide a simple answer with a live demonstration.

The approach involves iterating through the employees array and constructing objects with the desired structure, then pushing them into a final array.

Each object in the final array will include the following attributes:

name: corresponds to the name in the employees array (for each iteration)
job: for clarity, I will use job instead of job_id as indicated in your expected output. The job attribute is an object that includes
- id: representing the job_id from the employees array
- position: indicating the relevant position from the jobs array

To achieve the above outcome, we will utilize the reduce method to build the final array incrementally.

Furthermore, obtaining the corresponding position from the jobs array based on the job_id from the employees table can be accomplished using the find method which returns the first matching element from the jobs array.

With that explanation in mind, let's proceed with a live demonstration (including instructive comments):

const employees = [{
      name: 'Jason',
      job_id: '101'
    },
    {
      name: 'Sarah',
      job_id: '102'
    },
    {
      name: 'Jack',
      job_id: '102'
    }
  ],
  jobs = [{
      job_id: '101',
      position: 'Designer'
    },
    {
      job_id: '102',
      position: 'Developer'
    }
  ],
  /** 
   * "res" represents the resulting array after performing necessary operations 
   * The "reduce" method traverses the "employees" array to populate the "res" array accordingly
   */
  res = employees.reduce((a, c) => {
    /**
     * a: holds the prior value from the previous iteration - initially set to an empty array "[]" (referenced in the 3rd argument passed to the "reduce" method)
     * c: denotes the current element from the "employees" array for each iteration
     */

    /** appends an object adhering to the intended structure to the final array */
    a.push({
      name: c.name,
      job: {
        id: c.job_id,
        /** 
         * Locate the respective "position" based on the "job_id" of the current element within the "employees" array 
         * el: references the element from the "jobs" array during each iteration of the "find" method
         * the condition checks for an element where "job_id" matches the current element's "job_id," subsequently returning the associated "position"
         * once the "position" is found, it is assigned to the object being constructed
         */
        position: jobs.find(el => el.job_id == c.job_id).position
      }
    });
    /** return the array to enable the next iteration of "reduce" to proceed */
    return a;
  }, []);

/** display the result */
console.log(res);

While the presented demo is one way to accomplish the task, there are undoubtedly alternative ES6 methods available for crafting objects. For simplicity's sake, I have opted for straightforward and comprehensible approaches without utilizing intricate techniques.

For further insight, explore the reduce method documentation on MDN.

Delve into details about the find method via MDN resources.

What is the best way to combine two arrays containing objects?

Answer №1

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