How to cast pulumi.Output to string in TypeScript?

Q: How to cast pulumi.Output to string in TypeScript?

In Pulumi, you may want to cast a `pulumi.Output ` value to a string for simple console log purposes or for use within a part of your script where a raw string is needed. However, `pulumi.Output ` values represent a value which will be available in the future, not at the time of execution of your script, hence it requires a special method to deal with this. To handle this, we can use the `apply` method available on instances of `pulumi.Output `. This method allows you to provide a callback function, which will be invoked with the eventual outputted value. Here's an example of how to do it: ```typescript import * as pulumi from "@pulumi/pulumi"; let myOutput: pulumi.Output = /* some pulumi.Output here */ myOutput.apply(value => { // value here is automatically of type string console.log("My value: ", value); return value; }); ``` In this snippet, `value` inside the `apply` function will be of type `string` and can be used wherever a string is required. However, do remember that this function will be executed asynchronously in the future, not at the time your script is initially processed. The type `T` in `pulumi.Output ` can be any data type such as string, number, custom interface, etc. The `apply` method can also return a different type, which will change the type of the output. For example: ```typescript let myOutputNumber: pulumi.Output = myOutput.apply(value => { let numberValue = parseInt(value); console.log("My value as number: ", numberValue); return numberValue; // changing the Output type to number }); ``` Now, `myOutputNumber` is of type `pulumi.Output `, not `pulumi.Output `.

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Pulumi · Accepted Answer

In Pulumi, you may want to cast a `pulumi.Output` value to a string for simple console log purposes or for use within a part of your script where a raw string is needed. However, `pulumi.Output` values represent a value which will be available in the future, not at the time of execution of your script, hence it requires a special method to deal with this. To handle this, we can use the `apply` method available on instances of `pulumi.Output`. This method allows you to provide a callback function, which will be invoked with the eventual outputted value. Here's an example of how to do it: ```typescript import * as pulumi from "@pulumi/pulumi"; let myOutput: pulumi.Output = /* some pulumi.Output here */ myOutput.apply(value => { // value here is automatically of type string console.log("My value: ", value); return value; }); ``` In this snippet, `value` inside the `apply` function will be of type `string` and can be used wherever a string is required. However, do remember that this function will be executed asynchronously in the future, not at the time your script is initially processed. The type `T` in `pulumi.Output` can be any data type such as string, number, custom interface, etc. The `apply` method can also return a different type, which will change the type of the output. For example: ```typescript let myOutputNumber: pulumi.Output = myOutput.apply(value => { let numberValue = parseInt(value); console.log("My value as number: ", numberValue); return numberValue; // changing the Output type to number }); ``` Now, `myOutputNumber` is of type `pulumi.Output`, not `pulumi.Output`.