updating date format for files in javascript

Related: quartz-website-project-notes

---

3XP Summary

• Wanted to add “modified DD-MM-YYYY” for all my published notes
• Discovered lastmod.ts used date formats incompatible with mine
• Modified existing coerceDate to reformat, and added it next to “created” label

Problem

My frontmatter structure isn’t automatically compatible with the script that shows created on 01 Jan 2022, modified on 01 Jan 2025 because the dates are in DD-MM-YYYY format.

I’d already gone through most of my notes to add YAML frontmatter, and did not want to do that again! Javascript is still new to me, but I knew it could do functions like Python. Maybe there’s a way to transform the dates I have into dates for Quartz to process?

Process

Which file(s) control(s) dates?
I’d already asked in the Quartz discard how to find the file that hosts the 404 error text. I got some tips on how to navigate new-to-me repo’s, so I went spelunking into the plugins folder with high hopes.

After comparing the documentation and another digital garden, I discovered that whatever edit I needed to make was in the lastmod.ts file

How are dates processed by default?

• After importing relevant libraries/repos, it sets the default of where the date data can come from
• coerceDate is a function that parses the date strings as objects so JS can manipulate/handle them
• CreatedModifiedDate is a Quartz plugin (hosted in the lastmod.ts file) that takes the date information from my markdown files from different places (YAML frontmatter, git file tracking, etc). So now the code has my .md files’ dates
• the files’ dates are then changed via coerceDate, and this version of the notes are deployed to the website

Next Steps

• Write/modify a function(s) to detect DD-MM-YYYY format in my notes and transform them into YYYY-MM-DD (compatible with Quartz)
• Modify the Linter plugin I use so all dates are automatically linted with the YYYY-MM-DD format
• Modify my note templates to use the YYYY-MM-DD date format

Modify coerceDate in lastmod.ts to correct date formats
I didn’t need to change much:

• add an if/then statement that if it finds dates in DD-MM-YYYY format, then change it to YYYY-MM-DD and store that as the date object for downstream usage
• make sure the date reads like a string for file.date.data so the errors don’t accidentally throw!

function coerceDate(fp: string, d: any): Date { //nothing changed here  
    
  if (typeof d === 'string' && /^\d{2}-\d{2}-\d{4}$/.test(d)) {  
      // if notes are in xx-xx-xxxx pattern   
      const [day, month, year] = d.split('-');  
      // treat it as day-month-year  
      d = '${year}-${month}-${day}'  
      // and reformat it as year-month-day in xxxx-xx-xx format  

Modify fileData.dates in ContentMeta.tsx to show correct dates and labels

if (fileData.dates) {  
        segments.push("Neurogenesis on " + formatDate(fileData.dates.created))  
        segments.push("Signal refined on " + formatDate(fileData.dates.modified))  
      }  
  

Product

Success!

Now all the pages have their dates updated!!

Example screenshot showing for the note perform-at-80-percent-to-master-skills.