Accepts lazy evaluation for prefix opt

src/base.js

@@ -44,22 +44,25 @@ module.exports = function () {
   }
 
   Logdown._normalizeOpts = function (prefix, opts) {
-    if (typeof prefix !== 'string') {
-      throw new TypeError('prefix must be a string')
-    }
-
     opts = opts || {}
 
-    var markdown = opts.markdown === undefined ? true : Boolean(opts.markdown)
-    var prefixColor = opts.prefixColor || Logdown._getNextPrefixColor()
-    var logger = opts.logger || console
+    if (typeof prefix === 'object') {
+      var originalPrefixVal = prefix
+      prefix = prefix.prefix
+      opts = originalPrefixVal
+    } else if (typeof prefix === 'string') {
+      opts.prefix = prefix
+    }
 
-    return {
-      logger: logger,
-      markdown: markdown,
-      prefix: prefix,
-      prefixColor: prefixColor
+    if (typeof opts.prefix !== 'string') {
+      throw new TypeError('prefix must be a string')
     }
+
+    opts.markdown = opts.markdown === undefined ? true : Boolean(opts.markdown)
+    opts.prefixColor = opts.prefixColor || Logdown._getNextPrefixColor()
+    opts.logger = opts.logger || console
+
+    return opts
   }
 
   Logdown._getInitialState = function (opts) {

test/common/constructor.test.js

@@ -58,4 +58,14 @@ describe('logdown()', () => {
     log1.log('lorem')
     expect(logger.log).toHaveBeenCalled()
   })
+
+  it('accepts prefix as option argument key', () => {
+    const outsideVar = 'bar'
+    const log1 = logdown({
+      get prefix () {
+        return `foo-${outsideVar}`
+      }
+    })
+    expect(log1.opts.prefix).toEqual('foo-bar')
+  })
 })