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https://github.com/pomgui/chartjs-plugin-regression
Chart.js plugin to calculate and draw statistical linear, exponential, power, logarithmic, and polynomial regressions.
https://github.com/pomgui/chartjs-plugin-regression
chart regressions
Last synced: 3 months ago
JSON representation
Chart.js plugin to calculate and draw statistical linear, exponential, power, logarithmic, and polynomial regressions.
- Host: GitHub
- URL: https://github.com/pomgui/chartjs-plugin-regression
- Owner: pomgui
- License: isc
- Created: 2020-06-24T18:17:05.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2023-01-06T10:38:28.000Z (over 1 year ago)
- Last Synced: 2024-03-01T08:21:07.337Z (4 months ago)
- Topics: chart, regressions
- Language: TypeScript
- Homepage:
- Size: 95.7 KB
- Stars: 15
- Watchers: 3
- Forks: 11
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Lists
- awesome - regression
README
[](https://npmjs.org/package/chartjs-plugin-regression)
[](https://github.com/pomgui/chartjs-plugin-regression/blob/master/LICENSE)
[](https://npmjs.org/package/chartjs-plugin-regression)
# chartjs-plugin-regression
Chart.js plugin to calculate and draw statistical linear, exponential, power,
logarithmic, and polynomial regressions using chart datasets data.
The plugin, at the current version, uses the [regression](https://www.npmjs.com/package/regression)
npm package as its calculation engine.
### Important
- Only `bar`, `line`, and `scatter` chart types are supported.
- The plugin works just fine with [email protected], however that version may have some problems handling certain color configuration (not related with the plugin). No problems have been found with chart.js@^2.6.0.
- The plugin does not work with [email protected]
## Demo
For a better understanding of the capabilities of this plugin, please see this
[Live Demo](https://pomgui.github.io/chartjs-plugin-regression/demo/).
## Download
The [compressed](https://pomgui.github.io/chartjs-plugin-regression/dist/chartjs-plugin-regression-0.2.1.js)
version includes the regression package.
## Installation
npm install --save chartjs-plugin-regression
## Usage
For a single chart, it needs to be listed in plugins section.
### Example:
```javascript
new Chart(ctx, {
type: 'bar',
plugins: [
// This chart will use the plugin
ChartRegressions
],
data: {
...
datasets: [
{
...
// Configuration of the plugin per dataset (only will be drawn the datasets with this property)
regressions: {
type: 'linear',
line: { color: 'red', width: 3},
...
}
}
]
...
}
});
```
Also, it's possible to register the plugin for all the charts:
```javascript
Chart.plugins.register(ChartRegressions);
```
## Configuration
The plugin has three levels of configuration:
- global (for all the datasets in a chart)
- Per dataset
- Per section
There are common properties that the three levels share, and the priority of them are: section, dataset, and global.
### Common properties
Common to the three levels of configuration.
| Property | Description |
|---|---|
| type | Type of regression to be calculated. It can be 'copy', 'linear', 'exponential', 'power', 'polynomial', 'polynomial3', 'polynomial4', or 'logarithmic'. It also can be an array with a combination of these types, in which case the regression type with the best [_R²_](https://en.wikipedia.org/wiki/Coefficient_of_determination) will be drawn. |
| line | Line configuration for drawing the regression. It has the following properties: `{width, color, dash}` |
| calculation | Precision and polynomial order of the values returned by the regression calculations |
| extendPredictions | Previous sections predictions for the current section will be drawed as dashed lines |
| copy | Only if type=='copy'. Behavior of sections that copy other section's calculation |
Some considerations:
- `type`: polynomial3 and polynomial4 are pseudo-types added for convenience, they allow combinationss where the plugin will draw the regression with bigger R². Example:
```javascript
{
type: ['polynomial', 'polynomial3', 'polynomial4'],
calculation: {order 2}
}
```
- `calculation` has the following properties:
| Property | Description |
|---|---|
| `precision` | Determines how many decimals will have the results (default: 2). |
| `order` | Only for `polynomial` regression type, i.e. `polynomial3` and `polynomial4` are not affected by this property. Example: _ax² + bx + c_ has order 2. |
- `copy` has the following properties:
| Property | Description |
|---|---|
| `overwriteData` | Possible values: 'none', 'all', 'empty', or 'last'. Default: 'none'. It determines how the dataset's data will be overwritten in this section (empty: Only zero, undefined, or null data will be overwriten). **Obs.** the plugin is only prepared to overwrite numerical data arrays, e.g. `[1,2,3,...]`, scatter charts use xy data arrays, e.g. `[{x:1,y:1}, {x:2,y:2},...]`, with them the behavior is undetermined. In these cases it's better use `overwriteData: 'none'`. |
| `minValue` | Minimum value that the predicted value can be written into the data. |
| `maxValue` | Maximum value that the predicted value can be written into the data. |
### Global
The global configuration affects all the regressions calculated for all the datasets in the chart. It contains all the common properties and the following properties:
| Property | Description |
|---|---|
| onCompleteCalculation | Callback called when the regressions for all the datasets in a chart have been calculated |
Example:
```javascript
options: {
plugins: {
regressions: {
type: ['linear', 'polynomial'],
line: { color: 'blue', width: 3 },
onCompleteCalculation: function callback(chart){ ... }
}
}
}
```
### Per Dataset
It's possible to configure the regressions per dataset. The configuration will contain all the common properties and the following properties:
| Property | Description |
|---|---|
| sections | Array of sections of the data that shall be drawn. If not specified it's assumed `[{start:0,end:data.length-1}]` |
Example:
```javascript
datasets: [
{
...
// Configuration of the plugin per dataset (only will be drawn the datasets with this property)
regressions: {
type: ['linear','exponential'],
line: { color: '#ff0', width: 3},
calculation: { precision: 5 },
sections: [{startIndex: 10, endIndex: 50}],
...
}
}
]
```
### Per Section
Each section can be configured independently using all the common properties and the following properties:
| Property | Description |
|---|---|
| startIndex | Start index on dataset's data. Default: 0 |
| endIndex | End index on dataset's data. Default: data.length-1 |
| label | Label that will be drawn in the top of the right border line. Default: xaxis' label |
| copy.fromSectionIndex | Copy the predictions calculated by other section (the one with index fromSectionIndex) |
Example:
```javascript
datasets: [
{
...
// Configuration of the plugin per dataset (only will be drawn the datasets with this property)
regressions: {
line: { width: 3 },
calculation: { precision: 5 },
sections: [
{
type: ['linear','exponential'],
line: { color: 'red' },
startIndex: 10,
endIndex: 50
},
{
type: 'polynomial',
line: { color: 'green' },
startIndex: 50,
endIndex: 80,
calculation: { order: 4 }
},
]
}
}
...
]
```
## API
### .getDataset(chart, datasetIndex)
Returns the metadata associated to one dataset used internally by the plugin to work.
```javascript
var meta = ChartRegressions.getDataset(chart, datasetIndex);
```
This object provides the following information:
| Property | Description |
|---|---|
| `sections` | array of sections for each dataset (it will contain at least 1 section) |
| `getXY(x, y)` | Returns the canvas coordinates {x,y} for the data point `x, y`. |
| `topY` | Minimum y coordinate in the canvas. |
| `bottomY` | Maximum y coordinate in the canvas. |
### .getSections(chart, datasetIndex)
Returns the sections with all the properties calculated (some with default values, or inherited from dataset's plugin configuration or the global configuration in options).
This object provides the following information:
| Property | Description |
|---|---|
| `type` | array of regression types used to calculate and draw the section. |
| `startIndex` | Index of the dataset's data. |
| `endIndex` | Index of the dataset's data. |
| `line` | Configuration used to draw the lines {color, width, dash}. |
| `result` | Regression calculation result (see [demo](https://pomgui.github.io/chartjs-plugin-regression/demo/)) to see how to use this information. |
## Events
### onCompleteCalculation(chart)
The plugin provides one single event to inform when the calculation of all the regresions for a chart have been conmpleted.
This callback should be configured in the chart options.
Example:
```javascript
options: {
plugins: {
regressions: {
onCompleteCalculation: function callback(chart){ ... }
}
}
}
```
## License
The project is released under the [ISC license](https://github.com/pomgui/chartjs-plugin-regression/blob/master/LICENSE).