parameters.js

const Key = require('./key')

/**
 * Parameter wrapper
 */
class Parameters {
    /**
     * @param {string} [obj=null] "columnName"
     * @param {object} [obj=null] {'column1': 1, 'column2': 2}
     * @param {array} [obj=null] ['column1', 'column2']
     */
    constructor(obj) {
        this.obj = this.normalalizeObj(obj)

        this.values = []
        this.extra = {}
        this.keyNames = []

        if (Array.isArray(this.obj)) {
            // ['field1', 'field2'] format
            this.keyNames = this.obj
        } else {
            // {'field':'value'} format

            Object.entries(this.obj).filter(
                // Don't add fields starting with '_'. This is reserved for ordering / limit / offset.
                entry => !entry[0].startsWith('_')
            ).forEach(entry => {
                this.keyNames.push(entry[0])
                this.values.push(entry[1])
            })
        }
        this.isArray = this.keyNames.length > this.values.length
        this.keys = this.keyNames.map(key => {
            return new Key(key, this.isArray ? null : this.obj[key])
        })
    }

    /**
     * Convert object to valid value
     * @param {string} obj "columnName"
     * @param {object} obj {'column1': 1, 'column2': 2}
     * @param {array} obj ['column1', 'column2']
     * @returns {array} if array or string is given
     * @returns {object} if object or null || undefined is given
     */
    normalalizeObj(obj) {
        if (!obj) {
            return {}
        }
        if (typeof(obj) === 'string') {
            return [obj]
        }
        return obj
    }

    /**
     * Columns filtered by __eq should be indexed.
     *
     * @returns {array} column names which are filtered with __eq
     */
    getIndexableColumnNames() {
        return this.keys.filter(
            (key) => key.filter === 'eq'
        ).map(
            (key) => key.name
        )
    }

    /**
     * Get assignment string to be used in SQL queries.
     *
     * @param {string} [glue=", "]
     * @returns {string} "column1" = ?, "column2" = ?
     */
    getAssignString(glue) {
        return this.keys.map(key => key.string).join(glue || ', ')
    }

    /**
     * Get column string to be used in SQL queries
     *
     * @returns {string} "*" if no fields specified. Else '"column1", "column2"'
     */
    getColumnString() {
        if (this.keys.length === 0) {
            return '*'
        }
        return '"' + this.keyNames.join('","') + '"'
    }

    /**
     * Create comma devided question mark string with same length as columns to filter
     *
     * @returns {string} "?,?,?"
     */
    getQuestionMarkString() {
        return this.keys.filter(key => key.isParameter === true).map(() => '?').join(',')
    }

    getValues() {
        return this.keys.filter(key => key.isParameter === true).map((key) => key.value)
    }
}

module.exports = Parameters