feat: add setup method to change default options (#22)

Author: ybiquitous

README.md

@@ -73,6 +73,25 @@ b("element", { a: true, b: true });
 //=> "pre---block__element--a pre---block__element--b"
 ```
 
+### `setup()`
+
+Change default options.
+
+```ts
+import block, { setup } from "bem-ts";
+
+setup({
+  elementDelimiter: "_",
+  modifierDelimiter: "-",
+  prefix: "pre---",
+});
+
+const b = block("block");
+
+b("element", { a: true });
+//=> "pre---block_element-a"
+```
+
 ## Install
 
 ```sh

index.ts

@@ -1,8 +1,30 @@
 type Modifiers = { [key: string]: boolean; };
 
+const defaults = {
+  elementDelimiter: "__",
+  modifierDelimiter:  "--",
+  prefix: "",
+};
+
+export function setup(options: { elementDelimiter?: string, modifierDelimiter?: string, prefix?: string }) {
+  if (options.elementDelimiter) {
+    defaults.elementDelimiter = options.elementDelimiter;
+  }
+  if (options.modifierDelimiter) {
+    defaults.modifierDelimiter = options.modifierDelimiter;
+  }
+  if (options.prefix) {
+    defaults.prefix = options.prefix;
+  }
+}
+
 export default function bem(
   block: string,
-  { elementDelimiter = "__", modifierDelimiter =  "--", prefix = "" } = {},
+  {
+    elementDelimiter = defaults.elementDelimiter,
+    modifierDelimiter = defaults.modifierDelimiter,
+    prefix = defaults.prefix,
+  } = {},
 ) {
   return (elementOrModifiers?: string | Modifiers, modifiers?: Modifiers) => {
     let base = `${prefix}${block}`;

test.ts

@@ -1,4 +1,4 @@
-import block from ".";
+import block, { setup } from ".";
 
 describe("default", () => {
   const b = block("block");
@@ -115,3 +115,48 @@ describe("`prefix` option", () => {
       .toBe("pre---block__element--a pre---block__element--c");
   });
 });
+
+describe("`setup()`", () => {
+  setup({
+    elementDelimiter: "_",
+    modifierDelimiter: "-",
+    prefix: "pre---",
+  });
+
+  const b = block("block");
+
+  it("returns block", () => {
+    expect(b()).toBe("pre---block");
+  });
+
+  it("returns block with modifier", () => {
+    expect(b({ a: true, b: false })).toBe("pre---block-a");
+  });
+
+  it("returns block with multiple modifiers", () => {
+    expect(b({ a: true, b: false, c: true })).toBe("pre---block-a pre---block-c");
+  });
+
+  it("returns block with element", () => {
+    expect(b("element")).toBe("pre---block_element");
+  });
+
+  it("returns block with element and modifier", () => {
+    expect(b("element", { a: true, b: false })).toBe("pre---block_element-a");
+  });
+
+  it("returns block with element and multiple modifiers", () => {
+    expect(b("element", { a: true, b: false, c: true }))
+      .toBe("pre---block_element-a pre---block_element-c");
+  });
+
+  it("overrides options which was setup", () => {
+    const bl = block("block", { elementDelimiter: ":", modifierDelimiter: "/", prefix: "p-" });
+    expect(bl("element", { a: true })).toBe("p-block:element/a");
+  });
+
+  it("has no effect when empty options are passed", () => {
+    setup({});
+    expect(block("block")("element", { a: true })).toBe("pre---block_element-a");
+  });
+});