remove hard dependency on protobufjs

.eslintrc.js

@@ -11,5 +11,8 @@ module.exports = {
         'prettier',
         'prettier/@typescript-eslint',
         'plugin:prettier/recommended'
-    ]
+    ],
+    rules: {
+        '@typescript-eslint/no-var-requires': 'off'
+    }
 };

README.md

@@ -16,6 +16,16 @@ npm install @datadog/sketches-js
 yarn add @datadog/sketches-js
 ```
 
+When using Protobuf serialization, the [protobufjs](https://www.npmjs.com/package/protobufjs) module must also be installed manually:
+
+```sh
+# NPM
+npm install protobufjs
+
+# Yarn
+yarn add protobufjs
+```
+
 ## Usage
 
 ### Initialize a sketch

package.json

@@ -31,9 +31,7 @@
     "typecheck": "tsc --noEmit",
     "generate:proto": "pbjs -t static-module -w commonjs -o src/ddsketch/proto/compiled.js src/ddsketch/proto/DDSketch.proto && pbts -o src/ddsketch/proto/compiled.d.ts src/ddsketch/proto/compiled.js"
   },
-  "dependencies": {
-    "protobufjs": "^6.11.3"
-  },
+  "dependencies": {},
   "devDependencies": {
     "@types/jest": "^26.0.14",
     "@typescript-eslint/eslint-plugin": "^4.2.0",
@@ -43,6 +41,7 @@
     "eslint-plugin-prettier": "^3.1.4",
     "jest": "^26.4.2",
     "prettier": "^2.1.2",
+    "protobufjs": "^6.11.3",
     "ts-jest": "^26.4.0",
     "typescript": "^4.0.3"
   }

src/ddsketch/DDSketch.ts

@@ -7,7 +7,6 @@
 
 import { DenseStore } from './store';
 import { Mapping, KeyMapping, LogarithmicMapping } from './mapping';
-import { DDSketch as ProtoDDSketch } from './proto/compiled';
 
 const DEFAULT_RELATIVE_ACCURACY = 0.01;
 
@@ -186,6 +185,7 @@ class BaseDDSketch {
 
     /** Serialize a DDSketch to protobuf format */
     toProto(): Uint8Array {
+        const ProtoDDSketch = require('./proto/compiled').DDSketch;
         const message = ProtoDDSketch.create({
             mapping: this.mapping.toProto(),
             positiveValues: this.store.toProto(),
@@ -204,6 +204,7 @@ class BaseDDSketch {
      * @param buffer Byte array containing DDSketch in protobuf format (from DDSketch.toProto)
      */
     static fromProto(buffer: Uint8Array): DDSketch {
+        const ProtoDDSketch = require('./proto/compiled').DDSketch;
         const decoded = ProtoDDSketch.decode(buffer);
         const mapping = KeyMapping.fromProto(decoded.mapping);
         const store = DenseStore.fromProto(decoded.positiveValues);

src/ddsketch/mapping/CubicallyInterpolatedMapping.ts

@@ -67,6 +67,7 @@ export class CubicallyInterpolatedMapping extends KeyMapping {
     }
 
     _protoInterpolation(): IndexMappingProto.Interpolation {
-        return IndexMappingProto.Interpolation.CUBIC;
+        const { Interpolation } = require('../proto/compiled').IndexMapping;
+        return Interpolation.CUBIC;
     }
 }

src/ddsketch/mapping/KeyMapping.ts

@@ -78,6 +78,7 @@ export class KeyMapping implements Mapping {
     }
 
     toProto(): IIndexMapping {
+        const ProtoIndexMapping = require('../proto/compiled').IndexMapping;
         return ProtoIndexMapping.create({
             gamma: this.gamma,
             indexOffset: this._offset,
@@ -96,17 +97,18 @@ export class KeyMapping implements Mapping {
             throw Error('Failed to decode mapping from protobuf');
         }
 
+        const { Interpolation } = require('../proto/compiled').IndexMapping;
         const { interpolation, gamma, indexOffset } = protoMapping;
 
         switch (interpolation) {
-            case ProtoIndexMapping.Interpolation.NONE:
+            case Interpolation.NONE:
                 return LogarithmicMapping.fromGammaOffset(gamma, indexOffset);
-            case ProtoIndexMapping.Interpolation.LINEAR:
+            case Interpolation.LINEAR:
                 return LinearlyInterpolatedMapping.fromGammaOffset(
                     gamma,
                     indexOffset
                 );
-            case ProtoIndexMapping.Interpolation.CUBIC:
+            case Interpolation.CUBIC:
                 return CubicallyInterpolatedMapping.fromGammaOffset(
                     gamma,
                     indexOffset
@@ -127,6 +129,7 @@ export class KeyMapping implements Mapping {
     }
 
     _protoInterpolation(): ProtoIndexMapping.Interpolation {
-        return ProtoIndexMapping.Interpolation.NONE;
+        const { Interpolation } = require('../proto/compiled').IndexMapping;
+        return Interpolation.NONE;
     }
 }

src/ddsketch/mapping/LinearlyInterpolatedMapping.ts

@@ -50,6 +50,7 @@ export class LinearlyInterpolatedMapping extends KeyMapping {
     }
 
     _protoInterpolation(): IndexMappingProto.Interpolation {
-        return IndexMappingProto.Interpolation.LINEAR;
+        const { Interpolation } = require('../proto/compiled').IndexMapping;
+        return Interpolation.LINEAR;
     }
 }

src/ddsketch/mapping/LogarithmicMapping.ts

@@ -28,6 +28,7 @@ export class LogarithmicMapping extends KeyMapping {
     }
 
     _protoInterpolation(): IndexMappingProto.Interpolation {
-        return IndexMappingProto.Interpolation.NONE;
+        const { Interpolation } = require('../proto/compiled').IndexMapping;
+        return Interpolation.NONE;
     }
 }

src/ddsketch/store/DenseStore.ts

@@ -7,7 +7,7 @@
 
 import { sumOfRange } from './util';
 import type { Store } from './types';
-import { Store as ProtoStore, IStore } from '../proto/compiled';
+import { IStore } from '../proto/compiled';
 
 /** The default number of bins to grow when necessary */
 const CHUNK_SIZE = 128;
@@ -232,6 +232,7 @@ export class DenseStore implements Store<DenseStore> {
     }
 
     toProto(): IStore {
+        const ProtoStore = require('../proto/compiled').Store;
         return ProtoStore.create({
             contiguousBinCounts: this.bins,
             contiguousBinIndexOffset: this.offset