feat: impl flat tokens

src/core/flat-tokens.ts

@@ -0,0 +1,24 @@
+import { withPrefix } from './with-prefix'
+import { Shape, FlattenToken, Token, TokensMap } from './token.h'
+
+/**
+ * Returns flatten shape with tokens.
+ *
+ * @param tokens Map with tokens.
+ */
+export function flatTokens(tokens: TokensMap, __prefix__?: string): Shape<FlattenToken> {
+  const result: Shape<FlattenToken> = {}
+  for (const key in tokens) {
+    const transformedKey = withPrefix(key, __prefix__)
+    const maybeToken = tokens[key]
+    if (maybeToken.value === undefined) {
+      Object.assign(result, flatTokens(maybeToken as TokensMap, transformedKey))
+    } else {
+      result[transformedKey] = {
+        ...maybeToken as Token,
+        name: transformedKey,
+      }
+    }
+  }
+  return result
+}

src/core/with-prefix.ts

@@ -0,0 +1,12 @@
+/**
+ * Returns string with prefix.
+ *
+ * @param value Raw string.
+ * @param prefix Prefix for string.
+ */
+export function withPrefix(value: string, prefix?: string): string {
+  if (prefix === undefined) {
+    return value
+  }
+  return `${prefix}_${value}`
+}