Add a unit tests for typescript types (release-1.24 only)

Master will have a more robust test pipeline

package.json

@@ -22,7 +22,8 @@
     "build:site": "cp dist/function-plot.js site/js/function-plot.js",
     "start": "webpack-dev-server",
     "docs": "typedoc --excludeExternals --externalPattern \"**/node_modules/**\" --out site/docs src/index.ts",
-    "test": "jest"
+    "test": "jest",
+    "test:types": "check-dts test/** src/**"
   },
   "files": [
     "/dist"
@@ -67,6 +68,7 @@
     "@typescript-eslint/parser": "^5.37.0",
     "babel-eslint": "^10.1.0",
     "babel-loader": "^9.1.2",
+    "check-dts": "^0.7.2",
     "core-js": "^3.25.2",
     "dox": "^1.0.0",
     "eslint": "^8.23.1",

src/types.ts

@@ -149,7 +149,7 @@ export interface FunctionPlotDatum {
    * - interval: uses the interval arithmetic sampler to render a disjoint set of rectangles
    * - scatter: dotted line
    */
-  graphType?: 'polyline' | 'interval' | 'scatter'
+  graphType?: 'polyline' | 'interval' | 'scatter' | 'text'
 
   /**
    * The type of function to render

test/types.ts

@@ -0,0 +1,21 @@
+// test with `npx check-dts`
+import functionPlot from '../src/'
+
+functionPlot({
+  target: '#playground',
+  data: [
+    {
+      graphType: 'text',
+      location: [1, 1],
+      text: 'hello world'
+    },
+    {
+      graphType: 'text',
+      location: [-1, -1],
+      text: 'foo bar',
+      attr: {
+        'text-anchor': 'end'
+      }
+    }
+  ]
+})