#24 Add recipe to set up bem env

__sandbox__/config-and-ts/config-types.d.ts

@@ -0,0 +1,9 @@
+declare namespace Bem {
+  interface Options {
+    $default: {
+      elementDelimiter: "__"
+      modDelimiter: "--"
+      blockModKey: "$"  
+    } 
+  }  
+}

__sandbox__/config-and-ts/config.ts

@@ -0,0 +1,46 @@
+/// <reference path="./config-types.d.ts"/>
+
+export {}
+
+const options = {
+  current: {
+    elementDelimiter: "__" as const,
+    modDelimiter: "--" as const,
+    blockModKey: "$" as const,
+  }
+}
+
+
+export {
+  setOpts, getOpts
+}
+
+function setOpts<e extends string, m extends string, b extends string>(
+  elementDelimiter: e,
+  modDelimiter: m,
+  blockModKey: b
+) {
+  const current = {
+    elementDelimiter,
+    modDelimiter,
+    blockModKey
+  }
+
+  //@ts-expect-error
+  options.current = current
+}
+
+function getOpts() {
+  return options.current as {
+    elementDelimiter: "elementDelimiter" extends keyof Bem.Options
+    ? Bem.Options["elementDelimiter"]
+    : Bem.Options["$default"]["elementDelimiter"]
+    modDelimiter: "modDelimiter" extends keyof Bem.Options
+    ? Bem.Options["modDelimiter"]
+    : Bem.Options["$default"]["modDelimiter"]
+    blockModKey:
+    "blockModKey" extends keyof Bem.Options
+    ? Bem.Options["blockModKey"]
+    : Bem.Options["$default"]["blockModKey"]
+  }
+}

__sandbox__/config-and-ts/set-config.d.ts

@@ -0,0 +1,7 @@
+declare namespace Bem {
+  interface Options {
+    elementDelimiter: "_"
+    modDelimiter: "-"
+    blockModKey: "&"  
+  }
+}

__sandbox__/config-and-ts/set.ts

@@ -0,0 +1,14 @@
+/// <reference path="./set-config.d.ts" />
+
+import { setOpts, getOpts} from "./config";
+
+setOpts(
+  "_" as const,
+  "-" as const,
+  "&" as const
+)
+
+const x = getOpts().blockModKey
+, check: typeof x extends "&" ? true : false = true
+
+export {x, check}