A JavaScript library to draw and animate SVG path strokes.
See the DEMO.
Read this article to understand how it works.
HTML
Add the segment script, and define a path somewhere.
<script src="https://cdnjs.cloudflare.com/ajax/libs/segment-js/1.1.3/segment.js"></script>
<svg>
  <path id="my-path" ...>
</svg>JavaScript
Initialize a new Segment with the path. Then draw a segment of stroke every time you want with: .draw(begin, end, duration, options).
var myPath = document.getElementById("my-path"),
    segment = new Segment(myPath);
segment.draw("25%", "75% - 10", 1);npm install segment-js
The Segment constructor asks for 4 parameters:
- path: DOM element to draw.
 - begin (optional, default 
0): Length to start drawing the stroke. - end (optional, default 
100%): Length to finish drawing the stroke. - circular (optional, default 
false): Allowbeginandendvalues less than 0 and greater than 100%. 
| Name | Type | Default | Description | 
|---|---|---|---|
begin | 
string | 0 | Path length to start drawing. | 
end | 
string | 100% | Path length to finish drawing. | 
duration | 
float | 0 | Duration (in seconds) of the animation. | 
options | 
object | null | Options for animation in object notation. | 
Note that begin and end can be negative values and can be written in any of these ways:
- floatValue
 - percent
 - percent + floatValue
 - percent - floatValue
 
| Name | Type | Default | Description | 
|---|---|---|---|
delay | 
float | 0 | Waiting time (in seconds) to start drawing. | 
easing | 
function | linear | Easing function (normalized). I highly recommend d3-ease. | 
circular | 
boolean | false | If true, when the stroke reaches the end of the path it will resume at the beginning. The same applies in the opposite direction. | 
callback | 
function | null | Function to call when the animation is done. | 
Example
function cubicIn(t) {
    return t * t * t;
}
function done() {
    alert("Done!");
}
segment.draw("-25%", "75% - 10", 1, {delay: 0.5, easing: cubicIn, circular: true, callback: done});It's possible to animate the path stroke using another JavaScript library, like GSAP. Segments offers a method called strokeDasharray that is useful for this issue.
Here is an example using TweenLite (with CSSPlugin).
TweenLite.to(path, 1, { strokeDasharray: segment.strokeDasharray(begin, end) });