Use simple prng instead of a dependency

closes #2999

4 files changed, 23 insertions, 18 deletions

diff --git a/editors/code/package-lock.json b/editors/code/package-lock.json
index 712153c34..0760f870c 100644
--- a/editors/code/package-lock.json
+++ b/editors/code/package-lock.json
@@ -98,12 +98,6 @@
                 "@types/node": "*"
             }
         },
-        "@types/seedrandom": {
-            "version": "2.4.28",
-            "resolved": "https://registry.npmjs.org/@types/seedrandom/-/seedrandom-2.4.28.tgz",
-            "integrity": "sha512-SMA+fUwULwK7sd/ZJicUztiPs8F1yCPwF3O23Z9uQ32ME5Ha0NmDK9+QTsYE4O2tHXChzXomSWWeIhCnoN1LqA==",
-            "dev": true
-        },
         "@types/vscode": {
             "version": "1.41.0",
             "resolved": "https://registry.npmjs.org/@types/vscode/-/vscode-1.41.0.tgz",
@@ -691,11 +685,6 @@
             "integrity": "sha512-fZEwUGbVl7kouZs1jCdMLdt95hdIv0ZeHg6L7qPeciMZhZ+/gdesW4wgTARkrFWEpspjEATAzUGPG8N2jJiwbg==",
             "dev": true
         },
-        "seedrandom": {
-            "version": "3.0.5",
-            "resolved": "https://registry.npmjs.org/seedrandom/-/seedrandom-3.0.5.tgz",
-            "integrity": "sha512-8OwmbklUNzwezjGInmZ+2clQmExQPvomqjL7LFqOYqtmuxRgQYqOD3mHaU+MvZn5FLUeVxVfQjwLZW/n/JFuqg=="
-        },
         "semver": {
             "version": "6.3.0",
             "resolved": "https://registry.npmjs.org/semver/-/semver-6.3.0.tgz",
diff --git a/editors/code/package.json b/editors/code/package.json
index 06aa747fe..a46b0a82b 100644
--- a/editors/code/package.json
+++ b/editors/code/package.json
@@ -25,7 +25,6 @@
     },
     "dependencies": {
         "jsonc-parser": "^2.1.0",
-        "seedrandom": "^3.0.5",
         "vscode-languageclient": "^6.1.0"
     },
     "devDependencies": {
@@ -33,7 +32,6 @@
         "@rollup/plugin-node-resolve": "^6.1.0",
         "@rollup/plugin-typescript": "^2.0.0",
         "@types/node": "^12.12.25",
-        "@types/seedrandom": "^2.4.28",
         "@types/vscode": "^1.41.0",
         "rollup": "^1.30.1",
         "tslib": "^1.10.0",
diff --git a/editors/code/src/highlighting.ts b/editors/code/src/highlighting.ts
index 3d190c3ad..66216e0fc 100644
--- a/editors/code/src/highlighting.ts
+++ b/editors/code/src/highlighting.ts
@@ -1,6 +1,5 @@
 import * as vscode from 'vscode';
 import * as lc from 'vscode-languageclient';
-import seedrandom from 'seedrandom';
 
 import { ColorTheme, TextMateRuleSettings } from './color_theme';
 
@@ -70,9 +69,9 @@ interface Decoration {
 
 // Based on this HSL-based color generator: https://gist.github.com/bendc/76c48ce53299e6078a76
 function fancify(seed: string, shade: 'light' | 'dark') {
-    const random = seedrandom(seed);
+    const random = randomU32Numbers(hashString(seed))
     const randomInt = (min: number, max: number) => {
-        return Math.floor(random() * (max - min + 1)) + min;
+        return Math.abs(random()) % (max - min + 1) + min;
     };
 
     const h = randomInt(0, 360);
@@ -246,3 +245,23 @@ const TAG_TO_SCOPES = new Map<string, string[]>([
     ["keyword.unsafe", ["keyword.other.unsafe"]],
     ["keyword.control", ["keyword.control"]],
 ]);
+
+function randomU32Numbers(seed: number) {
+    let random = seed | 0;
+    return () => {
+        random ^= random << 13;
+        random ^= random >> 17;
+        random ^= random << 5;
+        random |= 0;
+        return random
+    }
+}
+
+function hashString(str: string): number {
+    let res = 0;
+    for (let i = 0; i < str.length; ++i) {
+        const c = str.codePointAt(i)!!;
+        res = (res * 31 + c) & ~0;
+    }
+    return res;
+}
diff --git a/editors/code/tsconfig.json b/editors/code/tsconfig.json
index d74169c29..e60eb8e5e 100644
--- a/editors/code/tsconfig.json
+++ b/editors/code/tsconfig.json
@@ -13,8 +13,7 @@
         "noUnusedParameters": true,
         "noImplicitReturns": true,
         "noFallthroughCasesInSwitch": true,
-        "newLine": "LF",
-        "esModuleInterop": true
+        "newLine": "LF"
     },
     "exclude": [
         "node_modules"