univ-conv/lib/converters/Base64Converter.js

The universal binary and text converter

import { decode } from "base64-arraybuffer";
import { AbstractConverter, _ } from "./AbstractConverter";
import { deleteStartLength, getStartEnd, hasNoStartLength, } from "./core";
import { isBrowser, newBufferFrom } from "./Environment";
import { getTextHelper } from "./StringUtil";
export class Base64Converter extends AbstractConverter {
    constructor() {
        super(...arguments);
        this.type = "base64";
    }
    empty() {
        return "";
    }
    is(input, options) {
        return typeof input === "string" && options.inputStringType === "base64";
    }
    async _from(input, options) {
        const univConv = _()._find(input, options);
        return await univConv.toBase64(input, options);
    }
    async _getStartEnd(input, options) {
        const size = await this.size(input);
        return getStartEnd(options, size);
    }
    _isEmpty(input) {
        return !input;
    }
    async _merge(chunks, options) {
        if (isBrowser) {
            const blob = await _().merge("blob", chunks, options);
            return await this.from(blob);
        }
        else {
            const u8 = await _().merge("uint8array", chunks, options);
            return await this.from(u8);
        }
    }
    _size(input) {
        const len = input.length;
        const baseLen = (len * 3) / 4;
        let padding = 0;
        for (let i = len - 1; input[i] === "="; i--) {
            padding++;
        }
        const size = baseLen - padding;
        return Promise.resolve(size);
    }
    async _toArrayBuffer(input, options) {
        const ab = decode(input);
        if (hasNoStartLength(options)) {
            return ab;
        }
        const { start, end } = await this._getStartEnd(input, options);
        return ab.slice(start, end);
    }
    async _toBase64(input, options) {
        if (hasNoStartLength(options)) {
            return input;
        }
        const u8 = await this._toUint8Array(input, options);
        return await this._from(u8, deleteStartLength(options));
    }
    async _toText(input, options) {
        const u8 = await this._toUint8Array(input, options);
        const textHelper = await getTextHelper();
        return await textHelper.bufferToText(u8, options);
    }
    async _toUint8Array(input, options) {
        const ab = await this._toArrayBuffer(input, options);
        return newBufferFrom(ab);
    }
}
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