getltdtkeys.mjs

import each from 'lodash-es/each.js'
import keys from 'lodash-es/keys.js'
import uniq from 'lodash-es/uniq.js'
import isearr from './isearr.mjs'


/**
 * 由ltdt提取不重複keys，各列物件只依自有可列舉鍵(length視為一般鍵)
 *
 * Unit Test: {@link https://github.com/yuda-lyu/wsemi/blob/master/test/getltdtkeys.test.mjs Github}
 * @memberOf wsemi
 * @param {Array} ltdt 輸入物件陣列
 * @returns {Array} 回傳不重複keys陣列
 * @example
 *
 * console.log(getltdtkeys([{ a: 123, b: 'xyz', c: '45op', d: null }, { a: 123.456, b: 'xyz', d: '45op', e: '' }]))
 * // => ['a', 'b', 'c', 'd', 'e']
 *
 */
function getltdtkeys(ltdt) {

    //check
    if (!isearr(ltdt)) {
        return []
    }

    //ks
    let ks = []
    each(ltdt, function(v) {
        //列物件只依自有可列舉鍵(lodash keys對不可寫偽稱Arguments之物件會依length走索引, R-OBJ-ITER-01), 列為真陣列者沿用keys(含空洞索引), Object(null)與Object(undefined)為{}
        let kst = Array.isArray(v) ? keys(v) : Object.keys(Object(v))
        ks = [...ks, ...kst]
        ks = uniq(ks)
    })

    return ks
}


export default getltdtkeys