tip: Add tip for null-coalescing

src/PowerShellTips/2024-01-07-use-null-coalescing-to-avoid-nulls-and-null-checks.ps1

@@ -0,0 +1,49 @@
+$tip = [tiPS.PowerShellTip]::new()
+$tip.CreatedDate = [DateTime]::Parse('2024-01-07')
+$tip.Title = 'Use null-coalescing to avoid nulls and null checks'
+$tip.TipText = @'
+PowerShell 7.0 introduced the null-coalescing operator (??). This can help reduce the number of explicit null checks you need to write.
+
+The null-coalescing operator syntax is as follows: <value> ?? <value-if-null>
+
+If the value on the left-hand side of the operator is not null, the statement on the right-hand side of the operator will not be evaluated.
+
+Null-coalescing can be used in expressions, conditional (if) statements, and variable assignments.
+'@
+$tip.Example = @'
+# $x is null so the value on the right-hand side of the operator is returned.
+> $x = $null
+> $x ?? 'Default value for x'
+Default value for x
+
+# $y is not null so the value on the left-hand side of the operator is returned.
+> $y = 'Explicit value for y'
+> $y ?? 'Default value for y'
+Explicit value for y
+
+# The null-coalescing operator can be used in variable assignments.
+# Since $x is null, $z is assigned the value of $y.
+> $z = $x ?? $y
+> $z
+Explicit value for y
+
+# Use the above expression ($z = $x ?? $y) instead of:
+if ($null -eq $x) {
+    $z = $y
+}
+'@
+$tip.Urls = @(
+	'https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_operators?view=powershell-7.4#null-coalescing-operator-'
+	'https://toastit.dev/2020/03/10/ps7now-null-conditional/'
+)
+$tip.Category = [tiPS.TipCategory]::Syntax # Community, Editor, Module, NativeCmdlet, Performance, Security, Syntax, Terminal, or Other.
+
+# Community: Social events and community resources. e.g. PowerShell Summit, podcasts, etc.
+# Editor: Editor tips and extensions. e.g. VSCode, ISE, etc.
+# Module: Modules and module tips. e.g. PSScriptAnalyzer, Pester, etc.
+# NativeCmdlet: Native cmdlet tips. e.g. Get-Process, Get-ChildItem, Get-Content, etc.
+# Performance: Tips to improve runtime performance. e.g. foreach vs ForEach-Object, ForEach-Object -Parallel, etc.
+# Security: Security tips. e.g. ExecutionPolicy, Constrained Language Mode, passwords, etc.
+# Syntax: Syntax tips. e.g. splatting, pipeline, etc.
+# Terminal: Terminal shortcuts and tips. e.g. PSReadLine, Windows Terminal, ConEmu, etc.
+# Other: Tips that don't fit into any of the other categories.

src/tiPS/PowerShellTips.json

@@ -454,5 +454,16 @@
       "https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_if#using-the-ternary-operator-syntax"
     ],
     "Category": 6
+  },
+  {
+    "CreatedDate": "2024-01-07T00:00:00",
+    "Title": "Use null-coalescing to avoid nulls and null checks",
+    "TipText": "PowerShell 7.0 introduced the null-coalescing operator (??). This can help reduce the number of explicit null checks you need to write.\r\n\r\nThe null-coalescing operator syntax is as follows: <value> ?? <value-if-null>\r\n\r\nIf the value on the left-hand side of the operator is not null, the statement on the right-hand side of the operator will not be evaluated.\r\n\r\nNull-coalescing can be used in expressions, conditional (if) statements, and variable assignments.",
+    "Example": "# $x is null so the value on the right-hand side of the operator is returned.\r\n> $x = $null\r\n> $x ?? 'Default value for x'\r\nDefault value for x\r\n\r\n# $y is not null so the value on the left-hand side of the operator is returned.\r\n> $y = 'Explicit value for y'\r\n> $y ?? 'Default value for y'\r\nExplicit value for y\r\n\r\n# The null-coalescing operator can be used in variable assignments.\r\n# Since $x is null, $z is assigned the value of $y.\r\n> $z = $x ?? $y\r\n> $z\r\nExplicit value for y\r\n\r\n# Use the above expression ($z = $x ?? $y) instead of:\r\nif ($null -eq $x) {\r\n    $z = $y\r\n}",
+    "Urls": [
+      "https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_operators?view=powershell-7.4#null-coalescing-operator-",
+      "https://toastit.dev/2020/03/10/ps7now-null-conditional/"
+    ],
+    "Category": 6
   }
 ]