How to create helper functions using dataviewjs?

[dgokcin]

Hello community

I was wondering what is the best way of reusing helper functions. Here is my use case:

• I have the following daily note template. Instead of having the code under done yesterday in my daily template, I would like to load it from a js file so that when I change the js file, all my existing daily notes are updated automatically. How can I make this work?

daily-template.md

---
tags: daily
retro-topics:
type: daily_note
creation date: <% tp.file.creation_date() %> 
modification date: <% tp.file.last_modified_date("dddd Do MMMM YYYY HH:mm:ss") %>
---

# daily updates

### Today
- [ ] 

### done yesterday
```tasks
done <% tp.date.now("YYYY-MM-DD", -1) %>
hide due date  
hide backlink
path includes work

Additionally, I also would like to re-use this function so that it always gets the last weekday instead of current day - 1.

function getLastWeekDay() {
    let date = new Date();
    let dayOfWeek = date.getDay();
    let diff = (dayOfWeek === 1 ? 3 : (dayOfWeek === 0 ? 2 : 1));
    date.setDate(date.getDate() - diff);
    console.log(date.toISOString().split('T')[0]);
    return date.toISOString().split('T')[0];
}
exports.getLastWeekDay = getLastWeekDay;