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class

wasi.WASI

class WASI

The WASI class provides the WASI system call API and additional convenience methods for working with WASI-based applications. Each WASI instance represents a distinct environment.

  • readonly wasiImport: Dict<any>

    wasiImport is an object that implements the WASI system call API. This object should be passed as the wasi_snapshot_preview1 import during the instantiation of a WebAssembly.Instance.

  • instance: object,
    options?: FinalizeBindingsOptions
    ): void;

    Set up WASI host bindings to instance without calling initialize() or start(). This method is useful when the WASI module is instantiated in child threads for sharing the memory across threads.

    finalizeBindings() requires that either instance exports a WebAssembly.Memory named memory or user specify a WebAssembly.Memory object in options.memory. If the memory is invalid an exception is thrown.

    start() and initialize() will call finalizeBindings() internally. If finalizeBindings() is called more than once, an exception is thrown.

  • getImportObject(): object;

    Return an import object that can be passed to WebAssembly.instantiate() if no other WASM imports are needed beyond those provided by WASI.

    If version unstable was passed into the constructor it will return:

    { wasi_unstable: wasi.wasiImport }

    If version preview1 was passed into the constructor or no version was specified it will return:

    { wasi_snapshot_preview1: wasi.wasiImport }
  • instance: object
    ): void;

    Attempt to initialize instance as a WASI reactor by invoking its _initialize() export, if it is present. If instance contains a _start() export, then an exception is thrown.

    initialize() requires that instance exports a WebAssembly.Memory named memory. If instance does not have a memory export an exception is thrown.

    If initialize() is called more than once, an exception is thrown.

  • instance: object
    ): number;

    Attempt to begin execution of instance as a WASI command by invoking its _start() export. If instance does not contain a _start() export, or if instance contains an _initialize() export, then an exception is thrown.

    start() requires that instance exports a WebAssembly.Memory named memory. If instance does not have a memory export an exception is thrown.

    If start() is called more than once, an exception is thrown.