Add string to boolean

blog_posts/javascript-string-to-boolean.md

@@ -0,0 +1,35 @@
+---
+title: "Tip: Convert a string to a boolean"
+shortTitle: String to boolean
+type: story
+tags: javascript,string,boolean,type
+expertise: beginner
+author: chalarangelo
+cover: blog_images/two-cities.jpg
+excerpt: Have you ever tried to convert the string represenation of a boolean to an actual boolean value? Here's a simple way to do it.
+firstSeen: 2022-09-14T05:00:00-04:00
+---
+
+Sometimes, one might run into the problem of converting the string representation of a value into the value itself. This is often straightforward, such as with numeric values. However, string representations of boolean values can be a bit trickier.
+
+This issue arises due to fact that any non-empty string is considered truthy in JavaScript. On top of that, strings can have different capitalization or whitespace, making it harder to compare them directly to a constant.
+
+To counteract this, it's often a good idea to use a couple of transformations, namely `String.prototype.toLowerCase()` and `String.prototype.trim()`, to make the string representation of the value more consistent. Additionally, an array of acceptable values might make it easier to perform the conversion in certain cases.
+
+```js
+const toBoolean = (value, truthyValues = ['true']) => {
+  const normalizedValue = String(value).toLowerCase().trim();
+  return truthyValues.includes(normalizedValue);
+};
+
+toBoolean('true'); // true
+toBoolean('TRUE'); // true
+toBoolean('True'); // true
+toBoolean('tRue '); // true
+toBoolean('false'); // false
+toBoolean('FALSE'); // false
+toBoolean('False'); // false
+toBoolean('fAlse '); // false
+toBoolean('YES', ['yes']); // true
+toBoolean('no', ['yes']); // false
+```