---
id: 5d8a4cfbe6b6180ed9a1ca09
title: Part 44
challengeType: 0
dashedName: part-44
---
# --description--
The line needs x and y values for each point of data. Chain `x` to the line and pass it a "d function". Here's how that will look:
```js
.x(d => d.year)
```
You will be passing your `data` array to this line function, where it will go through each item in the array(`d`) and create an x value based on the year(`d.year`).
This is the first place you have seen a "d function". These are common in D3 and that is how I will refer to them throughout this project.
# --hints--
test-text
```js
assert(
/const twitterLine = d3\.line\(\)\s*\.x\s*\(\s*d\s*=>\s*d\.year\s*\)/g.test(
code
)
);
```
# --seed--
## --before-user-code--
```html
D3 Dashboard
```
## --seed-contents--
```html
```
# --solutions--
```html
```