fix: build/type issue with DataGenerator (#671)

- Move around types to exclude mocks directory
- Remove import of seedrandom from dist files
- Add default rng function for DataGenerator

src/mocks/utils.ts

@@ -18,7 +18,7 @@
 
 import seedrandom from 'seedrandom';
 
-import { DataGenerator } from '../utils/data_generators/data_generator';
+import { DataGenerator, RandomNumberGenerator } from '../utils/data_generators/data_generator';
 
 /**
  * Forces object to be partial type for mocking tests
@@ -31,13 +31,6 @@ export const forcedType = <T extends object>(obj: Partial<T>): T => {
   return obj as T;
 };
 
-export type RandomNumberGenerator = (
-  min?: number,
-  max?: number,
-  fractionDigits?: number,
-  inclusive?: boolean,
-) => number;
-
 /**
  * Return rng function with optional `min`, `max` and `fractionDigits` params
  *

src/utils/data_generators/data_generator.ts

@@ -17,15 +17,31 @@
  * under the License. */
 
 import { Simple1DNoise } from './simple_noise';
-import { RandomNumberGenerator } from '../../mocks/utils';
+
+export type RandomNumberGenerator = (
+  min?: number,
+  max?: number,
+  fractionDigits?: number,
+  inclusive?: boolean,
+) => number;
+
+function defaultRNG(min = 0, max = 1, fractionDigits = 0, inclusive = true) {
+  const precision = Math.pow(10, Math.max(fractionDigits, 0));
+  const scaledMax = max * precision;
+  const scaledMin = min * precision;
+  const offset = inclusive ? 1 : 0;
+  const num = Math.floor(Math.random() * (scaledMax - scaledMin + offset)) + scaledMin;
+
+  return num / precision;
+}
 
 export class DataGenerator {
   private randomNumberGenerator: RandomNumberGenerator;
   private generator: Simple1DNoise;
   private frequency: number;
-  constructor(frequency = 500, randomNumberGenerator: RandomNumberGenerator) {
+  constructor(frequency = 500, randomNumberGenerator: RandomNumberGenerator = defaultRNG) {
     this.randomNumberGenerator = randomNumberGenerator;
-    this.generator = new Simple1DNoise(randomNumberGenerator);
+    this.generator = new Simple1DNoise(this.randomNumberGenerator);
     this.frequency = frequency;
   }
   generateBasicSeries(totalPoints = 50, offset = 0, amplitude = 1) {

src/utils/data_generators/simple_noise.ts

@@ -1,5 +1,3 @@
-import { RandomNumberGenerator } from '../../mocks/utils';
-
 /*
  * Licensed to Elasticsearch B.V. under one or more contributor
  * license agreements. See the NOTICE file distributed with
@@ -18,6 +16,8 @@ import { RandomNumberGenerator } from '../../mocks/utils';
  * specific language governing permissions and limitations
  * under the License. */
 
+import { RandomNumberGenerator } from './data_generator';
+
 export class Simple1DNoise {
   private maxVertices: number;
   private maxVerticesMask: number;

tsconfig.lib.json

@@ -5,5 +5,5 @@
   },
   "extends": "./tsconfig",
   "include": ["src/**/*"],
-  "exclude": ["**/*.test.*", "**/__mocks__"]
+  "exclude": ["**/*.test.*", "**/__mocks__", "src/mocks/**/*"]
 }