fixedstr/dist/index.js

Transforms fixed string to object and vice versa

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
function parseText(str) {
    return str.trim();
}
function textToString(field, value) {
    value = value || '';
    const endLength = Math.max(0, field.size + 1 - value.length);
    const end = new Array(endLength).join(' ');
    return value + end;
}
class FixedStr {
    static str(name, size) {
        return {
            name: name,
            size: size
        };
    }
    static strTrunc(name, size) {
        return {
            name: name,
            size: size,
            toFixedString: (field, value) => {
                const str = (value || '').substring(0, size);
                return textToString(field, str);
            }
        };
    }
    static number(name, size) {
        return {
            name: name,
            size: size,
            parse: Number,
            toFixedString: (field, value) => {
                const strVal = value && value.toString ? value.toString() : '0';
                const pad = new Array(Math.max(0, field.size + 1 - strVal.length)).join('0');
                return pad + strVal;
            }
        };
    }
    constructor(ObjectDefinitions) {
        this.objDef = ObjectDefinitions;
    }
    objectify(str) {
        let from = 0;
        str = str || '';
        return this.objDef.reduce((obj, field) => {
            const parse = field.parse || parseText;
            obj[field.name] = parse(str.substring(from, from + field.size));
            from += field.size;
            return obj;
        }, {});
    }
    stringify(obj) {
        return this.objDef.reduce((str, field) => {
            const toStr = field.toFixedString || textToString;
            const strValue = toStr(field, obj[field.name]);
            if (strValue && strValue.length > field.size) {
                throw new Error('truncation error on field: ' +
                    field.name +
                    ', size: ' +
                    field.size +
                    ', value: ' +
                    obj[field.name]);
            }
            return str + strValue;
        }, '');
    }
}
exports.FixedStr = FixedStr;
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