Merge 295fe153ad into aeb55efc3c

Hello, I've added a small blockquote below the description to indicate that this method of accessing an indefinite number of function arguments has been superseded by the use of the spread operator via rest parameters for ES6+ compatibility.

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1541 TILs and counting..._
+_1542 TILs and counting..._
 
 ---
 
@@ -405,6 +405,7 @@ _1541 TILs and counting..._
 - [Build For A Specific OS And Architecture](go/build-for-a-specific-os-and-architecture.md)
 - [Check If Cobra Flag Was Set](go/check-if-cobra-flag-was-set.md)
 - [Combine Two Slices](go/combine-two-slices.md)
+- [Detect If Stdin Comes From A Redirect](go/detect-if-stdin-comes-from-a-redirect.md)
 - [Do Something N Times](go/do-something-n-times.md)
 - [Find Executables Installed By Go](go/find-executables-installed-by-go.md)
 - [Format Date And Time With Time Constants](go/format-date-and-time-with-time-constants.md)

go/detect-if-stdin-comes-from-a-redirect.md

@@ -0,0 +1,59 @@
+# Detect If Stdin Comes From A Redirect
+
+Reading lines of input from `stdin` is flexible. And we may need our program to
+behave differently depending on where that input is coming from. For instance,
+if data is redirected or piped to our program, we scan and process it directly.
+Otherwise, we need to prompt the user to enter in specific info and go from
+there.
+
+We can detect whether [`os.Stdin`](https://pkg.go.dev/os#pkg-variables) is
+being piped to, redirected to, or whether we should prompt the user by looking
+at the file mode descriptor of
+[`os.Stdin.Stat()`](https://pkg.go.dev/os#File.Stat).
+
+```go
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func main() {
+	file, err := os.Stdin.Stat()
+	if err != nil {
+		fmt.Printf("Error checking stdin: %v\n", err)
+		os.Exit(1)
+	}
+
+	fromTerminal := (file.Mode() & os.ModeCharDevice) != 0
+	fromAPipe := (file.Mode() & os.ModeNamedPipe) != 0
+
+	if fromTerminal {
+		fmt.Println("This is Char Device mode, let's prompt user for input")
+		termScanner := bufio.NewScanner(os.Stdin)
+		for termScanner.Scan() {
+			fmt.Printf("- %s\n", termScanner.Text())
+			break;
+		}
+	} else if fromAPipe {
+		fmt.Println("This is Named Pipe mode, contents piped in")
+		pipeScanner := bufio.NewScanner(os.Stdin)
+		for pipeScanner.Scan() {
+			fmt.Printf("- %s\n", pipeScanner.Text())
+		}
+	} else {
+		fmt.Println("This means the input was redirected")
+		redirectScanner := bufio.NewScanner(os.Stdin)
+		for redirectScanner.Scan() {
+			fmt.Printf("- %s\n", redirectScanner.Text())
+		}
+	}
+}
+```
+
+If `os.ModeCharDevice` then we are connected to a character device, like the
+terminal. We can see if input is being piped in by checking against
+`os.ModeNamedPipe`. Otherwise, there are a variety of file modes and I'm
+willing to assume we're dealing with a regular file redirect at that point.

javascript/accessing-arguments-to-a-function.md

@@ -5,6 +5,8 @@ an array-like object with all of the arguments to the function. Even if not
 all of the arguments are referenced in the function signature, they can
 still be accessed via the `arguments` object.
 
+> For ES6+ compatibility, the `spread` operator used via [rest parameters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters) is preferred over the `arugments` object when accessing an abritrary number of function arguments.
+
 ```javascript
 function argTest(one) {
   console.log(one);