feat: Add support for passing a key to Deno.env() (#2952)

This adds a new op to get a single env var.

1 files changed, 10 insertions, 0 deletions

diff --git a/js/lib.deno_runtime.d.ts b/js/lib.deno_runtime.d.ts
index d0a720769..780503106 100644
--- a/js/lib.deno_runtime.d.ts
+++ b/js/lib.deno_runtime.d.ts
@@ -44,6 +44,16 @@ declare namespace Deno {
   export function env(): {
     [index: string]: string;
   };
+  /** Returns the value of an environment variable at invocation.
+   * If the variable is not present, `undefined` will be returned.
+   *
+   *       const myEnv = Deno.env();
+   *       console.log(myEnv.SHELL);
+   *       myEnv.TEST_VAR = "HELLO";
+   *       const newEnv = Deno.env();
+   *       console.log(myEnv.TEST_VAR == newEnv.TEST_VAR);
+   */
+  export function env(key: string): string | undefined;
   /**
    * Returns the current user's home directory.
    * Requires the `--allow-env` flag.