Merge pull request #8 from We-Gold/null-empty-feature

Remove Null or Empty Fields by Default

README.md

@@ -85,6 +85,8 @@ fetch("./somefile.gpx")
 	})
 ```
 
+_`parseGPX` has an additional optional argument `removeEmptyFields` which removes empty or null values from the output. It is true by default. This argument is also available in `parseGPXWithCustomParser`._
+
 ### Use the Parsed GPX
 
 ```js

lib/parse.ts

@@ -17,9 +17,10 @@ import {
  * Converts the given GPX XML to a JavaScript Object with the ability to convert to GeoJSON.
  *
  * @param gpxSource A string containing the source GPX XML
+ * @param removeEmptyFields Whether or not to remove null or undefined fields from the output
  * @returns A ParsedGPX with all of the parsed data and a method to convert to GeoJSON
  */
-export const parseGPX = (gpxSource: string) => {
+export const parseGPX = (gpxSource: string, removeEmptyFields: boolean = true) => {
 	const parseMethod = (gpxSource: string): Document | null => {
 		// Verify that we are in a browser
 		if (typeof document == undefined) return null
@@ -28,7 +29,7 @@ export const parseGPX = (gpxSource: string) => {
 		return domParser.parseFromString(gpxSource, "text/xml")
 	}
 
-	return parseGPXWithCustomParser(gpxSource, parseMethod)
+	return parseGPXWithCustomParser(gpxSource, parseMethod, removeEmptyFields)
 }
 
 /**
@@ -37,11 +38,13 @@ export const parseGPX = (gpxSource: string) => {
  *
  * @param gpxSource A string containing the source GPX XML
  * @param parseGPXToXML An optional method that parses gpx to a usable XML format
+ * @param removeEmptyFields Whether or not to remove null or undefined fields from the output
  * @returns A ParsedGPX with all of the parsed data and a method to convert to GeoJSON
  */
 export const parseGPXWithCustomParser = (
 	gpxSource: string,
-	parseGPXToXML: (gpxSource: string) => Document | null
+	parseGPXToXML: (gpxSource: string) => Document | null,
+	removeEmptyFields: boolean = true
 ): [null, Error] | [ParsedGPX, null] => {
 	// Parse the GPX string using the given parse method
 	const parsedSource = parseGPXToXML(gpxSource)
@@ -123,7 +126,7 @@ export const parseGPXWithCustomParser = (
 			time: null,
 		}
 
-		const rawElevation = parseFloat(getElementValue(waypoint, "ele"))
+		const rawElevation = parseFloat(getElementValue(waypoint, "ele") ?? "")
 		point.elevation = isNaN(rawElevation) ? null : rawElevation
 
 		const rawTime = getElementValue(waypoint, "time")
@@ -260,7 +263,7 @@ export const parseGPXWithCustomParser = (
 				point.extensions = extensions
 			}
 
-			const rawElevation = parseFloat(getElementValue(trackPoint, "ele"))
+			const rawElevation = parseFloat(getElementValue(trackPoint, "ele") ?? "")
 			point.elevation = isNaN(rawElevation) ? null : rawElevation
 
 			const rawTime = getElementValue(trackPoint, "time")
@@ -276,7 +279,14 @@ export const parseGPXWithCustomParser = (
 		output.tracks.push(track)
 	}
 
-	return [new ParsedGPX(output), null]
+	if (removeEmptyFields) {
+		deleteNullFields(output.metadata)
+		deleteNullFields(output.waypoints)
+		deleteNullFields(output.tracks)
+		deleteNullFields(output.routes)
+	}
+
+	return [new ParsedGPX(output, removeEmptyFields), null]
 }
 
 const parseExtensions = (
@@ -317,13 +327,13 @@ const parseExtensions = (
  * @param tag The tag of the child element that contains the desired data (e.g. "time" or "name")
  * @returns A string containing the desired value
  */
-const getElementValue = (parent: Element, tag: string): string => {
+const getElementValue = (parent: Element, tag: string): string | null => {
 	const element = parent.querySelector(tag)
 
 	// Extract and return the value within the parent element
 	if (element !== null) {
-		return element.firstChild?.textContent ?? element.innerHTML ?? ""
-	} else return ""
+		return element.firstChild?.textContent ?? element.innerHTML ?? null
+	} else return null
 }
 
 /**
@@ -353,3 +363,25 @@ const querySelectDirectDescendant = (
 		} else return null
 	}
 }
+
+export const deleteNullFields = <T>(object: T) => {
+	// Return non-object values as-is
+	if (typeof object !== 'object' || object === null || object === undefined) {
+		return 
+	}
+
+	// Remove null fields from arrays
+	if (Array.isArray(object)) {
+		object.forEach(deleteNullFields)
+		return
+	}
+
+	// Recursively remove null fields from object
+	for (const [key, value] of Object.entries(object)) {
+		if (value == null || value == undefined) {
+			delete (object as { [key: string]: any })[key]
+		} else {
+			deleteNullFields(value)
+		}
+	}
+}

lib/parsed_gpx.ts

@@ -9,6 +9,8 @@ import {
 	WaypointFeature,
 } from "./types"
 
+import { deleteNullFields } from "./parse"
+
 /**
  * Represents a parsed GPX object.
  * All internal data is accessible, and can be converted to GeoJSON.
@@ -19,13 +21,15 @@ export class ParsedGPX {
 	public waypoints: Waypoint[]
 	public tracks: Track[]
 	public routes: Route[]
+	private removeEmptyFields: boolean
 
-	constructor({ xml, metadata, waypoints, tracks, routes }: ParsedGPXInputs) {
+	constructor({ xml, metadata, waypoints, tracks, routes }: ParsedGPXInputs, removeEmptyFields: boolean = true) {
 		this.xml = xml
 		this.metadata = metadata
 		this.waypoints = waypoints
 		this.tracks = tracks
 		this.routes = routes
+		this.removeEmptyFields = removeEmptyFields
 	}
 
 	/**
@@ -107,6 +111,8 @@ export class ParsedGPX {
 			GeoJSON.features.push(feature)
 		}
 
+		if (this.removeEmptyFields) deleteNullFields(GeoJSON)
+
 		return GeoJSON
 	}
 }

lib/types.ts

@@ -1,28 +1,28 @@
 export type MetaData = {
-	name: string
-	description: string
+	name: string | null
+	description: string | null
 	link: Link | null
 	author: Author | null
-	time: string
+	time: string | null
 }
 
 export type Waypoint = {
-	name: string
-	symbol: string
-	comment: string
-	description: string
+	name: string | null
+	symbol: string | null
+	comment: string | null
+	description: string | null
 	latitude: number
 	longitude: number
 	elevation: number | null
 	time: Date | null
 }
 
 export type Track = {
-	name: string
-	comment: string
-	description: string
-	src: string
-	number: string
+	name: string | null
+	comment: string | null
+	description: string | null
+	src: string | null
+	number: string | null
 	link: Link | null
 	type: string | null
 	points: Point[]
@@ -32,11 +32,11 @@ export type Track = {
 }
 
 export type Route = {
-	name: string
-	comment: string
-	description: string
-	src: string
-	number: string
+	name: string | null
+	comment: string | null
+	description: string | null
+	src: string | null
+	number: string | null
 	link: Link | null
 	type: string | null
 	points: Point[]