✨ Add Trail#ifNull(fallback) method

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.3 (WIP)
+
+* Add `Trail#ifNull(fallback)` method
+
 ## 0.9.2 (2024-02-25)
 
 * Clear the entire `Develry.Request.cache` as soon as a non-GET request is made

lib/trail.js

@@ -1,5 +1,7 @@
 const CHAIN = Symbol('chain'),
-      GET_OR_EVALUATE = Symbol('getOrEvaluate');
+      GET_OR_EVALUATE = Symbol('getOrEvaluate'),
+      HAS_FALLBACK = Symbol('hasFallback'),
+      FALLBACK = Symbol('fallback');
 
 /**
  * Class that represents a path
@@ -21,6 +23,10 @@ const Trail = Fn.inherits('Develry.Placeholder', function Trail(chain) {
 	// The path pieces
 	this[CHAIN] = chain;
 
+	// There is no fallback by default
+	this[HAS_FALLBACK] = false;
+	this[FALLBACK] = undefined;
+
 	// Is this a root path?
 	this.is_root = chain[0] === '';
 
@@ -45,6 +51,12 @@ Trail.setStatic(function unDry(value) {
 	let result = Object.create(this.prototype);
 	result[CHAIN] = value.chain;
 	result.is_root = value.is_root;
+
+	if (value.fallback) {
+		result[HAS_FALLBACK] = true;
+		result[FALLBACK] = value.fallback.value;
+	}
+
 	return result;
 });
 
@@ -133,7 +145,7 @@ Trail.setStatic(function fromSlash(path) {
  *
  * @author   Jelle De Loecker <[email protected]>
  * @since    0.9.0
- * @version  0.9.0
+ * @version  0.9.3
  */
 Trail.setMethod(function toDry() {
 
@@ -145,18 +157,58 @@ Trail.setMethod(function toDry() {
 		value.is_root = true;
 	}
 
+	if (this[HAS_FALLBACK]) {
+		value.fallback = {value: this[FALLBACK]};
+	}
+
 	return {
 		value: value,
 	};
 });
 
+/**
+ * Create a shallow clone
+ *
+ * @author   Jelle De Loecker <[email protected]>
+ * @since    0.9.3
+ * @version  0.9.3
+ *
+ * @return   {Trail}
+ */
+Trail.setMethod(function shallowClone() {
+	let result = Object.create(this.constructor.prototype);
+	result[CHAIN] = this[CHAIN].slice(0);
+	result.is_root = this.is_root;
+	result[HAS_FALLBACK] = this[HAS_FALLBACK];
+	result[FALLBACK] = this[FALLBACK];
+	return result;
+});
+
+/**
+ * Set the fallback value for this trail.
+ * This will then be returned in case the value is null or undefined.
+ *
+ * @author   Jelle De Loecker <[email protected]>
+ * @since    0.9.3
+ * @version  0.9.3
+ *
+ * @param    {*}   fallback
+ *
+ * @return   {Trail}
+ */
+Trail.setMethod(function ifNull(fallback) {
+	this[HAS_FALLBACK] = true;
+	this[FALLBACK] = fallback;
+	return this;
+});
+
 /**
  * Get the value of the given path.
  * If `evaluate` is true and the last piece is a function, it will be called.
  *
  * @author   Jelle De Loecker <[email protected]>
  * @since    0.9.0
- * @version  0.9.0
+ * @version  0.9.3
  *
  * @param    {Object}   context
  * @param    {boolean}  evaluate
@@ -180,14 +232,14 @@ Trail.setMethod([GET_OR_EVALUATE], function internalGetOrEvaluate(context, evalu
 	for (index = 0; index < length; index++) {
 
 		if (context == null) {
-			return;
+			break;
 		}
 
 		key = chain[index];
 		value = context[key];
 
 		if (value == null) {
-			return;
+			break;
 		}
 
 		if (evaluate && index == last && typeof value == 'function') {
@@ -197,6 +249,10 @@ Trail.setMethod([GET_OR_EVALUATE], function internalGetOrEvaluate(context, evalu
 		}
 	}
 
+	if (value == null && this[HAS_FALLBACK]) {
+		value = this[FALLBACK];
+	}
+
 	return value;
 });
 

package.json

@@ -1,7 +1,7 @@
 {
 	"name": "protoblast",
 	"description": "Native object expansion library",
-	"version": "0.9.2",
+	"version": "0.9.3-alpha",
 	"author": "Jelle De Loecker <[email protected]>",
 	"keywords": [
 		"prototype",