more typing improvements [#112]

src/attribute.ts

@@ -69,7 +69,7 @@ export class TextAttr {
         break;
       }
     }
-    let transform;
+    let transform: string | ((z: number, f: Feature) => string) | undefined;
     if (typeof this.textTransform === "function") {
       transform = this.textTransform(z, f);
     } else {
@@ -139,14 +139,14 @@ export class FontAttr {
       }
     }
 
-    let size;
+    let size: number | ((z: number, f: Feature) => number) | undefined;
     if (typeof this.size === "function") {
       size = this.size(z, f);
     } else {
       size = this.size;
     }
 
-    let family;
+    let family: string | ((z: number, f: Feature) => string) | undefined;
     if (typeof this.family === "function") {
       family = this.family(z, f);
     } else {

src/frontends/static.ts

@@ -235,7 +235,11 @@ export class Static {
       canvas.height = height * dpr;
     }
     if (options.lang) canvas.lang = options.lang;
-    const ctx = canvas.getContext("2d")!;
+    const ctx = canvas.getContext("2d");
+    if (!ctx) {
+      console.error("Failed to initialize canvas2d context.");
+      return;
+    }
     ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
     return this.drawContext(ctx, width, height, latlng, display_zoom);
   }

src/symbolizer.ts

@@ -248,10 +248,6 @@ export function cubicBezier(
   };
 }
 
-function isFunction(obj: any) {
-  return !!(obj && obj.constructor && obj.call && obj.apply);
-}
-
 export class LineSymbolizer implements PaintSymbolizer {
   color: StringAttr;
   width: NumberAttr;
@@ -525,7 +521,7 @@ export class ShieldSymbolizer implements LabelSymbolizer {
       );
       ctx.fillStyle = this.fill.get(layout.zoom, f);
       ctx.font = font;
-      ctx.fillText(property!, -width / 2, 0);
+      ctx.fillText(property, -width / 2, 0);
     };
     return [{ anchor: a, bboxes: [bbox], draw: draw }];
   }
@@ -1104,10 +1100,10 @@ export class LineLabelSymbolizer implements LabelSymbolizer {
         if (lineWidth) {
           ctx.lineWidth = lineWidth;
           ctx.strokeStyle = this.stroke.get(layout.zoom, feature);
-          ctx.strokeText(name!, 0, 0);
+          ctx.strokeText(name, 0, 0);
         }
         ctx.fillStyle = this.fill.get(layout.zoom, feature);
-        ctx.fillText(name!, 0, 0);
+        ctx.fillText(name, 0, 0);
       };
       labels.push({
         anchor: candidate.start,

src/view.ts

@@ -74,7 +74,7 @@ export class View {
 
   public dataTilesForBounds(
     display_zoom: number,
-    bounds: any,
+    bounds: Bbox,
   ): Array<TileTransform> {
     const fractional = 2 ** display_zoom / 2 ** Math.ceil(display_zoom);
     const needed = [];