Implement formatShortNum helper

Author: Turbo87

app/helpers/format-short-num.js

@@ -0,0 +1,41 @@
+import Helper from '@ember/component/helper';
+import { service } from '@ember/service';
+
+/**
+ * This matches the implementation in https://github.com/rust-lang/crates_io_og_image/blob/v0.2.1/src/formatting.rs
+ * to ensure that we render roughly the same values in our user interface and the generated OpenGraph images.
+ */
+export default class FormatShortNumHelper extends Helper {
+  @service intl;
+
+  compute([value]) {
+    const THRESHOLD = 1500;
+    const UNITS = ['', 'K', 'M'];
+
+    let numValue = Number(value);
+    let unitIndex = 0;
+
+    // Keep dividing by 1000 until value is below threshold or we've reached the last unit
+    while (numValue >= THRESHOLD && unitIndex < UNITS.length - 1) {
+      numValue /= 1000;
+      unitIndex += 1;
+    }
+
+    let unit = UNITS[unitIndex];
+
+    // Special case for numbers without suffix - no decimal places
+    if (unitIndex === 0) {
+      return this.intl.formatNumber(value);
+    }
+
+    // For K and M, format with appropriate decimal places
+    // Determine number of decimal places to keep number under 4 chars
+    let fractionDigits = numValue < 10 ? 1 : 0;
+    let number = this.intl.formatNumber(numValue, {
+      minimumFractionDigits: fractionDigits,
+      maximumFractionDigits: fractionDigits,
+    });
+
+    return number + unit;
+  }
+}

tests/unit/helpers/format-short-num-test.gjs

@@ -0,0 +1,48 @@
+import { render } from '@ember/test-helpers';
+import { module, test } from 'qunit';
+
+import formatShortNum from 'crates-io/helpers/format-short-num';
+import { setupRenderingTest } from 'crates-io/tests/helpers';
+
+module('Unit | Helper | format-short-num', function (hooks) {
+  setupRenderingTest(hooks);
+
+  async function check(assert, input, expected) {
+    await render(<template>{{formatShortNum input}}</template>);
+    assert.dom().hasText(expected);
+  }
+
+  test('formats numbers without suffix (below 1500)', async function (assert) {
+    this.owner.lookup('service:intl').locale = 'en';
+
+    await check(assert, 0, '0');
+    await check(assert, 1, '1');
+    await check(assert, 1000, '1,000');
+    await check(assert, 1499, '1,499');
+  });
+
+  test('formats numbers with K suffix (1500 to 1500000)', async function (assert) {
+    this.owner.lookup('service:intl').locale = 'en';
+
+    await check(assert, 1500, '1.5K');
+    await check(assert, 2000, '2.0K');
+    await check(assert, 5000, '5.0K');
+    await check(assert, 10_000, '10K');
+    await check(assert, 50_000, '50K');
+    await check(assert, 100_000, '100K');
+    await check(assert, 500_000, '500K');
+    await check(assert, 999_999, '1,000K');
+  });
+
+  test('formats numbers with M suffix (above 1500000)', async function (assert) {
+    this.owner.lookup('service:intl').locale = 'en';
+
+    await check(assert, 1_500_000, '1.5M');
+    await check(assert, 2_000_000, '2.0M');
+    await check(assert, 5_000_000, '5.0M');
+    await check(assert, 10_000_000, '10M');
+    await check(assert, 50_000_000, '50M');
+    await check(assert, 100_000_000, '100M');
+    await check(assert, 1_000_000_000, '1,000M');
+  });
+});