feat: implementing oridinal colorscaling (#171)

* feat: implementing oridinal colorscaling

* Rewrite ScaleOridinal to fix typing issues

* fix: make `schemeCategorical` start with lower letter

* fix: rename `scale` to `valueAt`

packages/missing-coordinates/src/color/scaleOrdinal.ts

@@ -0,0 +1,36 @@
+export default class ScaleOrdinal {
+  // mapping from domain values to index.
+  private domainIndex = new Map();
+  // domain of possible values
+  private domainItems: string[] = [];
+  // range to be projected to
+  private rangeItems: string[] = [];
+
+  public valueAt(value: string | number): string | null {
+    const index = this.domainIndex.get(value.toString());
+    if (index === undefined) {
+      return null;
+    }
+    return this.rangeItems[index % this.rangeItems.length];
+  }
+
+  public domain(newDomain: string[] | number[]): ScaleOrdinal {
+    this.domainItems = [];
+    this.domainIndex = new Map();
+
+    newDomain.forEach((value) => {
+      const stringValue = value.toString();
+      if (!this.domainIndex.has(stringValue)) {
+        this.domainIndex.set(stringValue, this.domainItems.length);
+        this.domainItems.push(stringValue);
+      }
+    });
+
+    return this;
+  }
+
+  public range(newRange: string[]): ScaleOrdinal {
+    this.rangeItems = newRange;
+    return this;
+  }
+}

packages/missing-coordinates/src/color/schemes.ts

@@ -0,0 +1,26 @@
+export const schemeCategorical = {
+  Category10: [
+    "#1F77B4",
+    "#FF7F0E",
+    "#2CA02C",
+    "#D62728",
+    "#9467BD",
+    "#8C564B",
+    "#E377C2",
+    "#7F7F7F",
+    "#BCBD22",
+    "#17BECF",
+  ],
+  Tableau10: [
+    "#4E79A7",
+    "#F28E2C",
+    "#E15759",
+    "#76B7B2",
+    "#59A14F",
+    "#EDC949",
+    "#AF7AA1",
+    "#FF9DA7",
+    "#9C755F",
+    "#BAB0AB",
+  ],
+};