JavaScript Strategy Writing Guide

Due to the inherent characteristics of the JavaScript language (JavaScript's built-in strings only support ASCII and UTF-16 encoding, to avoid data loss), when encountering strings that cannot be encoded, an ArrayBuffer type will be returned. In all API interfaces of the FMZ Quant platform, wherever string parameters can be passed, ArrayBuffer type is also supported.

The following example demonstrates this feature in detail:

            javascript
            
            
function stringToHex(str) {
    let hex = '';
    for (let i = 0; i < str.length; i++) {
        const charCode = str.charCodeAt(i).toString(16);
        hex += charCode.length === 1 ? '0' + charCode : charCode;
    }
    return hex;
}

function main() {
    const inputString = "abc𠮷123";  // The Unicode code point of this "𠮷" character exceeds the 16-bit range
    // const inputString = "abcG123"; // If using abcG123 string for testing, the variable outputD will not be assigned as ArrayBuffer

    // Use the Encode function to encode inputString to hexadecimal encoding
    const encodedHex = Encode("raw", "string", "hex", inputString);
    Log(encodedHex);  // Content: 61 62 63 f0a0aeb7 31 32 33

    // Use custom stringToHex function to encode, unable to handle "𠮷" character, resulting in incorrect hexadecimal encoding
    const manuallyEncodedHex = stringToHex(inputString);
    Log(manuallyEncodedHex);  // Content: 61 62 63 d842dfb7 31 32 33

    // Successfully restore from hexadecimal encoding to string (variable inputString)
    const decodedString = Encode("raw", "hex", "string", encodedHex);
    Log(decodedString);

    // Unable to decode, returns ArrayBuffer, i.e., variable outputD is of ArrayBuffer type
    const outputD = Encode("raw", "hex", "string", manuallyEncodedHex);
    Log(outputD);

    // Verify the returned ArrayBuffer type variable outputD
    const bufferD = new Uint8Array(outputD);
    let hexBufferD = '';
    for (let i = 0; i < bufferD.length; i++) {
        hexBufferD += bufferD[i].toString(16).padStart(2, '0');
    }
    Log(hexBufferD);    // 61 62 63 d842dfb7 31 32 33
}