[util] Added more utils

src/util/index.js

@@ -1,4 +1,11 @@
-const stringify = require('json-stringify-safe');
+const _stringify = require('json-stringify-safe');
+
+const isObject = x => x && typeof x === 'object';
+
+const stringify = obj =>
+	isObject(obj)
+		? (obj.stack || _stringify(obj))
+		: obj;
 
 /* Returns true if a promise is passed */
 const isPromise = prom => prom && (typeof prom.then === 'function');
@@ -11,12 +18,20 @@ const liftPromise = (fn, thing) =>
 
 module.exports = {
 
+	/* Returns true if an object is passed */
+	isObject,
+
 	/* Returns true if a promise is passed */
 	isPromise,
 
 	/* Lift a value or promise into a function */
 	liftPromise,
 
+	/* Returns the element found at the given path or undefined */
+	path: obj =>
+		path =>
+			path.reduce((result, segment) => result && result[segment], obj),
+
 	/* Pipe a value or promise through any number of unary functions */
 	pipe: (...fns) =>
 		arg => fns.reduce((acc, fn) =>
@@ -28,6 +43,9 @@ module.exports = {
 	/* Maps a function over an array */
 	map : fn => x => x.map(fn),
 
+	/* Filter an array using provided function */
+	filter : fn => x => x.filter(fn),
+
 	/* Returns identity */
 	identity : x => x,
 
@@ -52,10 +70,11 @@ module.exports = {
 	),
 
 	/* Stringifies object or coerces to string */
-	stringify : obj =>
-		typeof obj === 'object'
-			? (obj.stack || stringify(obj))
-			: obj,
+	stringify,
+
+	/* Tagged Stringify */
+	taggedStringify: (strings, ...expr) => strings.reduce((acc, curr, i) =>
+		acc + curr + (stringify(expr[i]) || ''), ''),
 
 	/* Short circuits with given value on pred. Else calls function */
 	short : (pred, shorter) =>