PWA

node_modules/workbox-range-requests/src/utils/calculateEffectiveBoundaries.ts

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+/*
+  Copyright 2018 Google LLC
+
+  Use of this source code is governed by an MIT-style
+  license that can be found in the LICENSE file or at
+  https://opensource.org/licenses/MIT.
+*/
+
+import {WorkboxError} from 'workbox-core/_private/WorkboxError.js';
+import {assert} from 'workbox-core/_private/assert.js';
+import '../_version.js';
+
+/**
+ * @param {Blob} blob A source blob.
+ * @param {number} [start] The offset to use as the start of the
+ * slice.
+ * @param {number} [end] The offset to use as the end of the slice.
+ * @return {Object} An object with `start` and `end` properties, reflecting
+ * the effective boundaries to use given the size of the blob.
+ *
+ * @private
+ */
+function calculateEffectiveBoundaries(
+  blob: Blob,
+  start?: number,
+  end?: number,
+): {start: number; end: number} {
+  if (process.env.NODE_ENV !== 'production') {
+    assert!.isInstance(blob, Blob, {
+      moduleName: 'workbox-range-requests',
+      funcName: 'calculateEffectiveBoundaries',
+      paramName: 'blob',
+    });
+  }
+
+  const blobSize = blob.size;
+
+  if ((end && end > blobSize) || (start && start < 0)) {
+    throw new WorkboxError('range-not-satisfiable', {
+      size: blobSize,
+      end,
+      start,
+    });
+  }
+
+  let effectiveStart: number;
+  let effectiveEnd: number;
+
+  if (start !== undefined && end !== undefined) {
+    effectiveStart = start;
+    // Range values are inclusive, so add 1 to the value.
+    effectiveEnd = end + 1;
+  } else if (start !== undefined && end === undefined) {
+    effectiveStart = start;
+    effectiveEnd = blobSize;
+  } else if (end !== undefined && start === undefined) {
+    effectiveStart = blobSize - end;
+    effectiveEnd = blobSize;
+  }
+
+  return {
+    start: effectiveStart!,
+    end: effectiveEnd!,
+  };
+}
+
+export {calculateEffectiveBoundaries};