Add booleans

README.md

@@ -2,6 +2,9 @@
 
 [![NPM version](https://badge.fury.io/js/slate-hyperprint.svg)](http://badge.fury.io/js/slate-hyperprint)
 
+Slate's data model has been built with serialization in mind. Specifically, its text nodes are defined in a way that makes them easier to read at a glance, but also easy to serialize to common formats like HTML and Markdown.
+And, because Slate uses plain JSON for its data, you can write serialization logic very easily.
+
 A library to convert Slate models to their slate-hyperscript representation.
 
 You can use `slate-hyperprint` as a library to:

src/bin/booleans.js

@@ -0,0 +1,57 @@
+// @flow
+import isPlainObject from 'is-plain-object';
+import printComplexDataStructure from './printComplexDataStructure';
+
+/*
+Based on
+https://github.com/algolia/react-element-to-jsx-string/blob/master/src/formatter/formatPropValue.js
+*/
+
+const escape = (s: string): string => s.replace(/"/g, '"');
+
+/*
+ * Print a tag attribute, for example as 'key={value}' or 'key="value"' or 'key'
+ */
+function printAttributeValue(value: any): string {
+    if (typeof value === 'number') {
+        return `{${String(value)}}`;
+    }
+
+    if (typeof value === 'string') {
+        return `"${escape(value)}"`;
+    }
+
+    // > "Symbols (new in ECMAScript 2015, not yet supported in Flow)"
+    // @see: https://flow.org/en/docs/types/primitives/
+    // $FlowFixMe: Flow does not support Symbol
+    if (typeof value === 'symbol') {
+        throw new Error('not implemented');
+    }
+
+    if (typeof value === 'function') {
+        throw new Error('not implemented');
+    }
+
+    if (value instanceof Date) {
+        return `{new Date("${value.toISOString()}")}`;
+    }
+
+    if (isPlainObject(value) || Array.isArray(value)) {
+        return `{${printComplexDataStructure(value)}}`;
+    }
+
+    return `{${String(value)}}`;
+}
+
+/*
+ * Print a tag attribute to 'key={value}' or 'key' for `true`
+ */
+function printAttribute(key: string, value: any) {
+    if (value === true) {
+        return key;
+    }
+
+    return `${key}=${printAttributeValue(value)}`;
+}
+
+export default printAttribute;