wkr-util/esm/validators/validateNoDatabaseDuplicates.js

Utility library for wkr project.

import {compose, curry, map, get, toInt, values, liftA} from '@cullylarson/f'
import {messageObj, simpleValidationResult} from '@cullylarson/validate'
import {query} from '@cullylarson/mysql'

// ignoreIdInfo can just be an id (will ignore the row with this id when looking for dupes), or an array.
// if it's an array, the first value is the id to ignore and the second is the placeholder to use instead of just a '?'
// (used if you need to convert the id using an sql function like UUID_TO_BIN).
export default curry((pool, tableName, idColumnName, ignoreIdInfo, paramNameToColumnName, _, params) => {
    ignoreIdInfo = liftA(ignoreIdInfo)

    const whereInfo = compose(
        xs => {
            const ignoreId = get(0, undefined, ignoreIdInfo)
            const ignoreValuePlaceholder = get(1, '?', ignoreIdInfo)

            return !ignoreId
                ? xs
                : [...xs, [
                    `${idColumnName} != ${ignoreValuePlaceholder}`,
                    ignoreId,
                ]]
        },
        values,
        map((columnName, paramName) => {
            return [
                `${columnName} = ?`, // the condition query
                params[paramName], // the value to fill in for the '?'
            ]
        }),
    )(paramNameToColumnName)

    // nothing to check
    if(!whereInfo.length) return null

    const where = whereInfo.map(get(0, '')).join(' AND ')
    const whereValues = whereInfo.map(get(1, ''))

    return query(pool, `SELECT COUNT(*) as count FROM ${tableName} WHERE ${where}`, whereValues)
        .then(get(['results', 0, 'count'], 1))
        .then(toInt(1))
        .then(count => {
            return count > 0
                ? simpleValidationResult(messageObj('is-duplicate', 'This entry already exists.'))
                : simpleValidationResult()
        })
})