Simplify flow modules.

flow.js

@@ -1,5 +1,3 @@
-import createFlow from './.internal/createFlow.js';
-
 /**
  * Creates a function that returns the result of invoking the given functions
  * with the `this` binding of the created function, where each successive
@@ -7,7 +5,7 @@ import createFlow from './.internal/createFlow.js';
  *
  * @since 3.0.0
  * @category Util
- * @param {...(Function|Function[])} [funcs] The functions to invoke.
+ * @param {Function[]} [funcs] The functions to invoke.
  * @returns {Function} Returns the new composite function.
  * @see flowRight
  * @example
@@ -20,6 +18,22 @@ import createFlow from './.internal/createFlow.js';
  * addSquare(1, 2);
  * // => 9
  */
-const flow = createFlow();
+function flow(funcs) {
+  const length = funcs ? funcs.length : 0;
+  let index = length;
+  while (index--) {
+    if (typeof funcs[index] != 'function') {
+      throw new TypeError('Expected a function');
+    }
+  }
+  return function(...args) {
+    let index = 0;
+    let result = length ? funcs[index].apply(this, args) : args[0];
+    while (++index < length) {
+      result = funcs[index].call(this, result);
+    }
+    return result;
+  };
+}
 
 export default flow;