createEncoder

Call Signature

createEncoder<TFrom, TSize>(encoder): FixedSizeEncoder<TFrom, TSize>

Creates an Encoder by filling in the missing encode function using the provided write function and either the fixedSize property (/api/functions/for FixedSizeEncoders) or the getSizeFromValue function (/api/functions/for VariableSizeEncoders).

Instead of manually implementing encode, this utility leverages the existing write function and the size helpers to generate a complete encoder. The provided encode method will allocate a new Uint8Array of the correct size and use write to populate it.

Type Parameters

Type Parameter	Description
`TFrom`	The type of the value to encode.
`TSize` extends `number`	The fixed size of the encoded value in bytes (for fixed-size encoders).

Parameters

Parameter	Type	Description
`encoder`	`Omit`<`FixedSizeEncoder`<`TFrom`, `TSize`>, `"encode"`>	An encoder object that implements `write`, but not `encode`. - If the encoder has a `fixedSize` property, it is treated as a FixedSizeEncoder. - Otherwise, it is treated as a VariableSizeEncoder.

Returns

FixedSizeEncoder<TFrom, TSize>

A fully functional Encoder with both write and encode methods.

Examples

Creating a custom fixed-size encoder.

const encoder = createEncoder({
    fixedSize: 4,
    write: (value: number, bytes, offset) => {
        bytes.set(new Uint8Array([value]), offset);
        return offset + 4;
    },
});
 
const bytes = encoder.encode(42);
// 0x2a000000

Creating a custom variable-size encoder:

const encoder = createEncoder({
    getSizeFromValue: (value: string) => value.length,
    write: (value: string, bytes, offset) => {
        const encodedValue = new TextEncoder().encode(value);
        bytes.set(encodedValue, offset);
        return offset + encodedValue.length;
    },
});
 
const bytes = encoder.encode("hello");
// 0x68656c6c6f

Remarks

Note that, while createEncoder is useful for defining more complex encoders, it is more common to compose encoders together using the various helpers and primitives of the @solana/codecs package.

Here are some alternative examples using codec primitives instead of createEncoder.

// Fixed-size encoder for unsigned 32-bit integers.
const encoder = getU32Encoder();
const bytes = encoder.encode(42);
// 0x2a000000
 
// Variable-size encoder for 32-bytes prefixed UTF-8 strings.
const encoder = addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder());
const bytes = encoder.encode("hello");
// 0x0500000068656c6c6f
 
// Variable-size encoder for custom objects.
type Person = { name: string; age: number };
const encoder: Encoder<Person> = getStructEncoder([
    ['name', addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder())],
    ['age', getU32Encoder()],
]);
const bytes = encoder.encode({ name: "Bob", age: 42 });
// 0x03000000426f622a000000

See

Call Signature

createEncoder<TFrom>(encoder): VariableSizeEncoder<TFrom>

Type Parameters

Type Parameter	Description
`TFrom`	The type of the value to encode.

Parameters

Parameter	Type	Description
`encoder`	`Omit`<`VariableSizeEncoder`<`TFrom`>, `"encode"`>	An encoder object that implements `write`, but not `encode`. - If the encoder has a `fixedSize` property, it is treated as a FixedSizeEncoder. - Otherwise, it is treated as a VariableSizeEncoder.

Returns

VariableSizeEncoder<TFrom>

A fully functional Encoder with both write and encode methods.

Examples

Creating a custom fixed-size encoder.

const encoder = createEncoder({
    fixedSize: 4,
    write: (value: number, bytes, offset) => {
        bytes.set(new Uint8Array([value]), offset);
        return offset + 4;
    },
});
 
const bytes = encoder.encode(42);
// 0x2a000000

Creating a custom variable-size encoder:

const encoder = createEncoder({
    getSizeFromValue: (value: string) => value.length,
    write: (value: string, bytes, offset) => {
        const encodedValue = new TextEncoder().encode(value);
        bytes.set(encodedValue, offset);
        return offset + encodedValue.length;
    },
});
 
const bytes = encoder.encode("hello");
// 0x68656c6c6f

Remarks

Note that, while createEncoder is useful for defining more complex encoders, it is more common to compose encoders together using the various helpers and primitives of the @solana/codecs package.

Here are some alternative examples using codec primitives instead of createEncoder.

// Fixed-size encoder for unsigned 32-bit integers.
const encoder = getU32Encoder();
const bytes = encoder.encode(42);
// 0x2a000000
 
// Variable-size encoder for 32-bytes prefixed UTF-8 strings.
const encoder = addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder());
const bytes = encoder.encode("hello");
// 0x0500000068656c6c6f
 
// Variable-size encoder for custom objects.
type Person = { name: string; age: number };
const encoder: Encoder<Person> = getStructEncoder([
    ['name', addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder())],
    ['age', getU32Encoder()],
]);
const bytes = encoder.encode({ name: "Bob", age: 42 });
// 0x03000000426f622a000000

See

Call Signature

createEncoder<TFrom>(encoder): Encoder<TFrom>

Type Parameters

Type Parameter	Description
`TFrom`	The type of the value to encode.

Parameters

Parameter	Type	Description
`encoder`	`Omit`<`FixedSizeEncoder`<`TFrom`, `number`>, `"encode"`> \| `Omit`<`VariableSizeEncoder`<`TFrom`>, `"encode"`>	An encoder object that implements `write`, but not `encode`. - If the encoder has a `fixedSize` property, it is treated as a FixedSizeEncoder. - Otherwise, it is treated as a VariableSizeEncoder.

Returns

Encoder<TFrom>

A fully functional Encoder with both write and encode methods.

Examples

Creating a custom fixed-size encoder.

const encoder = createEncoder({
    fixedSize: 4,
    write: (value: number, bytes, offset) => {
        bytes.set(new Uint8Array([value]), offset);
        return offset + 4;
    },
});
 
const bytes = encoder.encode(42);
// 0x2a000000

Creating a custom variable-size encoder:

const encoder = createEncoder({
    getSizeFromValue: (value: string) => value.length,
    write: (value: string, bytes, offset) => {
        const encodedValue = new TextEncoder().encode(value);
        bytes.set(encodedValue, offset);
        return offset + encodedValue.length;
    },
});
 
const bytes = encoder.encode("hello");
// 0x68656c6c6f

Remarks

Note that, while createEncoder is useful for defining more complex encoders, it is more common to compose encoders together using the various helpers and primitives of the @solana/codecs package.

Here are some alternative examples using codec primitives instead of createEncoder.

// Fixed-size encoder for unsigned 32-bit integers.
const encoder = getU32Encoder();
const bytes = encoder.encode(42);
// 0x2a000000
 
// Variable-size encoder for 32-bytes prefixed UTF-8 strings.
const encoder = addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder());
const bytes = encoder.encode("hello");
// 0x0500000068656c6c6f
 
// Variable-size encoder for custom objects.
type Person = { name: string; age: number };
const encoder: Encoder<Person> = getStructEncoder([
    ['name', addEncoderSizePrefix(getUtf8Encoder(), getU32Encoder())],
    ['age', getU32Encoder()],
]);
const bytes = encoder.encode({ name: "Bob", age: 42 });
// 0x03000000426f622a000000

createEncoder

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