andrewpietiladotcom/lib/MimeMessage.js

import MimeHeader from "./MimeHeader.js";

class MimeMessage {
    constructor(message) {
        this.headers = [];
        this.body = "";
        let messageLines = message.split('\r\n');
        let inHeaders = true;
        let currentMessageLine = 0;
        let currentHeader = messageLines[currentMessageLine];
        currentMessageLine++;
        while (inHeaders) {
            if (messageLines[currentMessageLine] === "") {
                inHeaders = false;
                this.headers.push(new MimeHeader(currentHeader));
            } else if (messageLines[currentMessageLine].match(/^\s/)) {
                    currentHeader = `${currentHeader}\r\n${messageLines[currentMessageLine]}`;
                } else {
                    this.headers.push(new MimeHeader(currentHeader));
                    currentHeader = `${messageLines[currentMessageLine]}`;
                }
            currentMessageLine++;
        }

        this.body = messageLines.slice(currentMessageLine).join("\r\n");
    }

    prependHeader(header) {
        if ( header instanceof MimeHeader ) {
            this.headers.unshift(header);
        } else if ( typeof header === "string" ) {
            this.headers.unshift(new MimeHeader(header) );
        } else {
            throw new TypeError("Invalid object passed to prependHeader");
        }
    }

    getFirstHeaderOf(key) {
        return this.headers.find((header) => header.key.toLowerCase() === key.toLowerCase());
    }

    getAllHeaderOf(key) {
        return this.headers.filter((header) => header.key.toLowerCase() === key.toLowerCase());
    }

    removeFirstHeaderOf(key) {
        let indexOfFirst = this.headers.findIndex((header) => header.key.toLowerCase() === key.toLowerCase());
        this.headers = [...this.headers.slice(0, indexOfFirst), ...this.headers.slice(indexOfFirst+1)];
    }

    removeAllHeaderOf(key) {
        this.headers = this.headers.filter((header) => header.key.toLowerCase() !== key.toLowerCase());
    }

    toString() {
        return `${this.headers.map((header) => header.toString()).join("\r\n")}\r\n\r\n${this.body}`;
    }
}

export default MimeMessage;