Reimplementing GPX imports.

src/lib/gpx.test.ts

@@ -0,0 +1,33 @@
+import { assert } from 'console';
+import { findStartTime } from './gpx';
+
+describe('findStartTime', () => {
+  test('to be undefined for a string', () => {
+    const start = findStartTime('');
+    expect(start).toBeUndefined();
+  });
+  test('to be undefined for an object without time key', () => {
+    const start = findStartTime({ foo: 'foo', bar: 'bar' });
+    expect(start).toBeUndefined();
+  });
+  test('to be the time value for an object with a time key', () => {
+    const start = findStartTime({ foo: 'foo', time: 'bar' });
+    expect(start).toEqual('bar');
+  });
+  test('to be the lowest time value for an object with several time keys', () => {
+    const start = findStartTime({
+      foo: { time: 'foo' },
+      time: 'bar',
+      bar: { time: 'a' },
+    });
+    expect(start).toEqual('a');
+  });
+  test('to be the lowest time value for an array with several objects with time keys', () => {
+    const start = findStartTime({
+      foos: [{ time: 'foo' }, { time: '0' }],
+      time: 'bar',
+      bar: { time: 'a' },
+    });
+    expect(start).toEqual('0');
+  });
+});

src/lib/gpx.ts

@@ -0,0 +1,19 @@
+const min = (s1?: string, s2?: string) => {
+  return s1! < s2! ? s1 : s2;
+};
+
+export const findStartTime = (x: any, startTime?: string) => {
+   if (typeof x === 'object') {
+    let newStartTime = startTime;
+
+    for (const key in x) {
+      if (key === 'time') {
+        newStartTime = min(newStartTime, x[key]);
+      } else {
+        newStartTime =  findStartTime(x[key], newStartTime);
+      }
+    }
+    return newStartTime;
+  }
+  else return startTime;
+};