diff --git a/src/serve_data.js b/src/serve_data.js
index 4e2acaf..99459b9 100644
--- a/src/serve_data.js
+++ b/src/serve_data.js
@@ -249,9 +249,20 @@ export const serve_data = {
         if (fetchTile == null) return res.status(204).send();
 
         let data = fetchTile.data;
-        var param = { long: bbox[0], lat: bbox[1], encoding, format, tile_size: TILE_SIZE, z: zoom, x: xy[0], y: xy[1] };
+        var param = {
+          long: bbox[0],
+          lat: bbox[1],
+          encoding,
+          format,
+          tile_size: TILE_SIZE,
+          z: zoom,
+          x: xy[0],
+          y: xy[1],
+        };
 
-        res.status(200).send(await serve_rendered.getTerrainElevation(data, param));
+        res
+          .status(200)
+          .send(await serve_rendered.getTerrainElevation(data, param));
       } catch (err) {
         return res
           .status(500)
diff --git a/src/serve_light.js b/src/serve_light.js
index 6f1d446..13aa84c 100644
--- a/src/serve_light.js
+++ b/src/serve_light.js
@@ -6,5 +6,8 @@ export const serve_rendered = {
   init: (options, repo, programOpts) => {},
   add: (options, repo, params, id, programOpts, dataResolver) => {},
   remove: (repo, id) => {},
-  getTerrainElevation: (data, param) => { param["elevation"] = "not supported in light"; return param; },
+  getTerrainElevation: (data, param) => {
+    param['elevation'] = 'not supported in light';
+    return param;
+  },
 };
diff --git a/src/serve_rendered.js b/src/serve_rendered.js
index d7eadf8..3dc3cd5 100644
--- a/src/serve_rendered.js
+++ b/src/serve_rendered.js
@@ -1459,43 +1459,43 @@ export const serve_rendered = {
     delete repo[id];
   },
 
-    /**
+  /**
    * Get the elevation of terrain tile data by rendering it to a canvas image
-  * @param {object} data `The background color (or empty string for transparent).
-  * @param {object} format A sharp format.
-  * @returns {object}
-  */
-  getTerrainElevation: async function(data, param) {
+   * @param {object} data The background color (or empty string for transparent).
+   * @param {object} param Required parameters (coordinates e.g.)
+   * @returns {object}
+   */
+  getTerrainElevation: async function (data, param) {
     return await new Promise(async (resolve, reject) => {
       const image = new Image();
       image.onload = async () => {
-        const canvas = createCanvas(param["tile_size"], param["tile_size"]);
+        const canvas = createCanvas(param['tile_size'], param['tile_size']);
         const context = canvas.getContext('2d');
         context.drawImage(image, 0, 0);
 
         // calculate pixel coordinate of tile,
         // see https://developers.google.com/maps/documentation/javascript/examples/map-coordinates
-        let siny = Math.sin((param["lat"] * Math.PI) / 180);
+        let siny = Math.sin((param['lat'] * Math.PI) / 180);
         // Truncating to 0.9999 effectively limits latitude to 89.189. This is
         // about a third of a tile past the edge of the world tile.
         siny = Math.min(Math.max(siny, -0.9999), 0.9999);
-        const xWorld = param["tile_size"] * (0.5 + param["long"] / 360);
+        const xWorld = param['tile_size'] * (0.5 + param['long'] / 360);
         const yWorld =
-          param["tile_size"] *
+          param['tile_size'] *
           (0.5 - Math.log((1 + siny) / (1 - siny)) / (4 * Math.PI));
 
-        const scale = 1 << param["z"];
+        const scale = 1 << param['z'];
 
-        const xTile = Math.floor((xWorld * scale) / param["tile_size"]);
-        const yTile = Math.floor((yWorld * scale) / param["tile_size"]);
+        const xTile = Math.floor((xWorld * scale) / param['tile_size']);
+        const yTile = Math.floor((yWorld * scale) / param['tile_size']);
 
-        const xPixel = Math.floor(xWorld * scale) - xTile * param["tile_size"];
-        const yPixel = Math.floor(yWorld * scale) - yTile * param["tile_size"];
+        const xPixel = Math.floor(xWorld * scale) - xTile * param['tile_size'];
+        const yPixel = Math.floor(yWorld * scale) - yTile * param['tile_size'];
         if (
           xPixel < 0 ||
           yPixel < 0 ||
-          xPixel >= param["tile_size"] ||
-          yPixel >= param["tile_size"]
+          xPixel >= param['tile_size'] ||
+          yPixel >= param['tile_size']
         ) {
           return reject('Out of bounds Pixel');
         }
@@ -1504,21 +1504,21 @@ export const serve_rendered = {
         const green = imgdata.data[1];
         const blue = imgdata.data[2];
         let elevation;
-        if (param["encoding"] === 'mapbox') {
+        if (param['encoding'] === 'mapbox') {
           elevation = -10000 + (red * 256 * 256 + green * 256 + blue) * 0.1;
-        } else if (param["encoding"] === 'terrarium') {
+        } else if (param['encoding'] === 'terrarium') {
           elevation = red * 256 + green + blue / 256 - 32768;
         } else {
           elevation = 'invalid encoding';
         }
-        param["elevation"] = elevation;
-        param["red"] = red;
-        param["green"] = green;
-        param["blue"] = blue;
+        param['elevation'] = elevation;
+        param['red'] = red;
+        param['green'] = green;
+        param['blue'] = blue;
         resolve(param);
       };
       image.onerror = (err) => reject(err);
-      if (param["format"] === 'webp') {
+      if (param['format'] === 'webp') {
         try {
           const img = await sharp(data).toFormat('png').toBuffer();
           image.src = img;
diff --git a/src/utils.js b/src/utils.js
index 41ae101..41fa831 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -14,6 +14,9 @@ export const allowedTileSizes = allowedOptions(['256', '512']);
 
 import { fileURLToPath } from 'url';
 
+/**
+ *
+ */
 export function isLight() {
   const __filename = fileURLToPath(import.meta.url);
   const __dirname = path.dirname(__filename);