javascript JS Goupby-like algorithm for Object arrays

[IncrediblePony]

Hey guys!

 

I have run into at problem where I have two different arrays:

 

// Sample data from function getTimeIntervals()

[

  RowDataPacket { issue_id: 117648, seconds_elapsed_issue: '318' },
  RowDataPacket { issue_id: 118090, seconds_elapsed_issue: '8940' },
  RowDataPacket { issue_id: 118092, seconds_elapsed_issue: '5357' },
  RowDataPacket { issue_id: 118199, seconds_elapsed_issue: '41604' },
  RowDataPacket { issue_id: 118351, seconds_elapsed_issue: '3778' },
  RowDataPacket { issue_id: 118395, seconds_elapsed_issue: '2974' },
  RowDataPacket { issue_id: 119014, seconds_elapsed_issue: '37680' },
  RowDataPacket { issue_id: 119729, seconds_elapsed_issue: '15006' },
  RowDataPacket { issue_id: 119735, seconds_elapsed_issue: '26389' },
  RowDataPacket { issue_id: 119742, seconds_elapsed_issue: '67' },

  ...
 ]

 

// Sample data from function getIssueData()

[

  RowDataPacket { project_id: 1445, issue_id: 121007 },
  RowDataPacket { project_id: 1445, issue_id: 120921 },
  RowDataPacket { project_id: 1445, issue_id: 121011 },
  RowDataPacket { project_id: 1420, issue_id: 120454 },
  RowDataPacket { project_id: 1420, issue_id: 121004 },
  RowDataPacket { project_id: 1445, issue_id: 120868 },
  RowDataPacket { project_id: 1467, issue_id: 121010 },
  RowDataPacket { project_id: 1445, issue_id: 120870 },
  RowDataPacket { project_id: 1420, issue_id: 121009 },
  RowDataPacket { project_id: 1445, issue_id: 120018 },

  ...

]

 

Now... What I want to do is avoid using a nested for loop for this because using nested for loops is in my opinion the slowest possible way to solve this task (O(n^2) time if I'm not mistaken): I want to add up all elapsed seconds from an issue under the 'project_id' value from the second array.

 

This means producing a result that looks something like this:

 

[

  {project_id: 1445, seconds_elapsed: '270129'},

  {project_id: 1467, seconds_elapsed: '16012'},

  ...

]

 

Does anyone have a solution to this particular problem? Because those I have found out there on the internet, I either do not understand or does not apply to my use case.

-- Thanks!

[bleedblue]

Use a foreach statement

[IncrediblePony]

9 minutes ago, bleedblue said:

Use a foreach statement

If I use a foreach statement I still have to nest the statement right? Or am I wrong there? Please specify

[keskparane]

I would have thought there would be 2 options.

1. For elapsed seconds of a specific project match items with the issue id of first array.
2. For elapsed seconds of each project add first array items then apply to second array items.

Either way only requires a single pass on each array.

[IncrediblePony]

13 minutes ago, keskparane said:

I would have thought there would be 2 options.

1. For elapsed seconds of a specific project match items with the issue id of first array.
2. For elapsed seconds of each project add first array items then apply to second array items.

Either way only requires a single pass on each array.

So would you just have me do a pass of each array gather up data and then loop again? I'm not sure what you mean here..

[keskparane]

Well do you want elapsed time of each project or just elapsed time for a specific project?

[IncrediblePony]

Just now, keskparane said:

Well do you want elapsed time of each project or just elapsed time for a specific project?

I want elapsed time for each project calculated by the issues's seconds elapsed

[keskparane]

iterate through the first array and save the elapsed time sums to a new object with their id

iterate through the second array and save the project ids to a new object with the corresponding elapsed time

you now have an object that can access elapsed times by project id

[IncrediblePony]

3 minutes ago, keskparane said:

iterate through the first array and save the elapsed time sums to a new object with their id

iterate through the second array and save the project ids to a new object with the corresponding elapsed time

you now have an object that can access elapsed times by project id

Ah - that's what you meant Thanks - will implement