Add residuals prop, upgrade packages

.travis.yml

@@ -4,7 +4,7 @@ env:
     - GIT_COMMITTED_AT=$(if [ "$TRAVIS_PULL_REQUEST" == "false" ]; then git log -1 --pretty=format:%ct; else git log -1 --skip 1 --pretty=format:%ct; fi)
 language: node_js
 node_js:
-  - "6.1"
+  - "8.10.0"
 before_script:
   - curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
   - chmod +x ./cc-test-reporter

README.md

@@ -51,6 +51,7 @@ Below are the default values for the configuration parameter.
 - `equation`: an array containing the coefficients of the equation
 - `string`: A string representation of the equation
 - `points`: an array containing the predicted data in the domain of the input
+- `residuals`: an array containing the difference between predicted data and source data in the domain of the input
 - `r2`: the coefficient of determination (<i>R</i><sup>2</sup>)
 - `predict(x)`: This function will return the predicted value
 
@@ -80,6 +81,7 @@ const result = regression.polynomial(data, { order: 3 });
 
 ## Development
 
-- Install the dependencies with `npm install`
-- To build the assets in the `dist` directory, use `npm run build`
-- You can run the tests with: `npm run test`.
+- Install the dependencies with `yarn install`
+- To build the assets in the `dist` directory, use `yarn build`
+- You can run the tests with: `yarn test` or `yarn test --watch`.
+- `yarn lint --fix`

babel.config.js

@@ -0,0 +1,17 @@
+const presets = [
+  [
+    '@babel/env',
+    {
+      targets: {
+        edge: '17',
+        firefox: '60',
+        chrome: '67',
+        safari: '11.1',
+      },
+      useBuiltIns: 'usage',
+      corejs: 3,
+    },
+  ],
+];
+
+module.exports = { presets };