[Javascript学习99---代码片段收集]

文件权限修改

var Promise = require("bluebird");var fs = Promise.stringifyAll(require("fs"));function changeFileToNonRootWritable(path) {    return fs.chmodAsync(path, "664").catch((err) => {        logger.error("chmod '%s' fails: %s", path, err);        return Promise.reject();    });}function changeFileToNonRootReadable(path) {    return fs.chmodAsync(path, "644").catch((err) => {        logger.error("chmod '%s' fails: %s", path, err);        return Promise.reject();    });}

更改文件所属群组

var Promise = require('promise');var child_process = Promise.promisifyAll(require('child_process'));function changeGroup(gid /*: string(groupID) */, path /*: filePath */) /*: promise(reject | resolve) */ {    if (gid) {        var command = "chgrp " + gid + " " + path;        logger.info("Executing command ", command);        return child_process.execAsync(command).catch(function(err) {            logger.error("Could not change group for " + path + " (err: " + err.code + ")");            return Promise.reject();        });    } else {        return Promise.resolve();    }}

函数返回函数

// 值得学习函数返回带参数的函数。Mescom.prototype.successfulStatusOrThrow = function successfulStatusOrThrow(message) {    return function(response) {        if (!hasSuccessfulStatus(response)) {            throw new Mescom.MescomError(message, response);        } else {            return response;        }    };};// 函数调用mescom.sendAndWaitResponse(msg, mescom.Filter.byId(mescom.messageId.RROM_CONFIGURATION_RESP_MSG))// 注意 mescom.successfulStatusOrThrow("RROM configuration failed") 实际上返回的是一个带参数的匿名函数，所以当前面filter出来的结果就作为这个函数的参数传进去了。        .then(mescom.successfulStatusOrThrow("RROM configuration failed"))        .error(logError)        .catch(Promise.TimeoutError, handleTimeout);

如果Array里面没有找到string则push该string进去

//场景1function isStrNotInAryThenPush(ary, str) {    ary.indexOf(str) != -1 || ary.push(str);    //ES6    ary.includes(str) || ary.push(str);}// 场景2var _ = require('lodash');function pushData(collections/*: object */, value, key/*: string */)/*: object */ {    (collections[key] || collections[key]=[]).push(value);    return collections}pushData({a:[1], b:[2, 4]}, 3, 'c');// => {a:[1], b:[2, 4], c:[3]}// 场景3var _ = require('lodash');_.reduce({ 'a': 1, 'b': 2, 'c': 1 }, function(result, value, key) {  //如果存在就push到存在的数组里，否则就创建新数组push进去  (result[value] || (result[value] = [])).push(key);  return result;}, {});// => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)

macObjects.map(getMacAddress).some(isSameWithInputMacAddress);

function isSameMacAddress(inputMacAddress) {        return onlineImTree.getImTree()            .then(nodeFinder.getActiveBtsLNode)            .then(compareMacAddressFromActiveLNode);        function compareMacAddressFromActiveLNode(activeBtsLNode) {            const macObjects = activeBtsLNode ? activeBtsLNode.findByClassPath(ETHIF_R) : [];            return macObjects.map(getMacAddress).some(isSameWithInputMacAddress);        }        function getMacAddress(macObject) {            const parameters = macObject.getDecodedParameters();            return parameters ? parameters.macAddr : '';        }        function isSameWithInputMacAddress(macAddr) {            return macAddr.replace(macReplaceRegex, '') === inputMacAddress.replace(macReplaceRegex, '');        }    }

按年保存数据

/** * [groupPrsByYear description] * @param  {[type]} arr [description] * @return {[type]:}     [{year1:{date: "year1", data:[{d1}, {d2}]}}] */function groupPrsByYear(arr/*: array */) /*: array */{    var mytmpData = {};    (arr||[]).forEach(function(d) {        //group data by year.        var tmpTime = (moment(d.createtimestamp*1000).format('YYYY'));        var tmpFind = _.has(mytmpData, tmpTime);        if(tmpFind) {            mytmpData[tmpTime]["data"].push(d);        }else {            mytmpData[tmpTime] = {date:tmpTime, data: [d]};        }    });//end (arr||[]).forEach(function(d)    return mytmpData;}// 代码可以像下面这样简化：function groupBy_interval(results, interval){    return _.groupBy(results, d => faultCommons.formatDate(d.createtimestamp*1000, interval));}//faultCommons.formatDate 如下：function formatDate(timestamp, interval) {    var formats = {day: 'YYYY-MM-DD', isoweek: 'YYYY[-]WW', month: 'YYYY[-]MM', year: 'YYYY', week: 'YYYY[-]ww'};    return timestamp.toString().length === 11 //unix timestamp        ? moment(timestamp*1000).format(formats[interval])        : moment(timestamp).format(formats[interval]);}

根据soted数据，filter第一次符合条件的数据。

function find_first_item(obj, srcKey, target) {    return _.find(obj, d => faultCommons.isInArray(target, d[srcKey]));}

api 到数据过滤需要item，到Echart函数

function fault_ncdr_chartDraw(data, graph_ID, tableParams) {    // var data ={"results": [{"date":"2017-03","stats":[{"name":"NCDR(A&B)","num":39},{"name":"A-Critical","num":20},{"name":"B-Major","num":19},{"name":"C-Minor","num":8},{"name":"Baseline","num":43},{"name":"NCDR Cumulative","num":131},{"name":"A-Critical Cumulative","num":56},{"name":"B-Major Cumulative","num":75},{"name":"Monthly Target","num":0},{"name":"Target Cumulative","num":0}]},    //          {"date":"2017-04","stats":[{"name":"NCDR(A&B)","num":0},{"name":"A-Critical","num":0},{"name":"B-Major","num":0},{"name":"C-Minor","num":0},{"name":"Baseline","num":46},{"name":"NCDR Cumulative","num":131},{"name":"A-Critical Cumulative","num":56},{"name":"B-Major Cumulative","num":75},{"name":"Monthly Target","num":0},{"name":"Target Cumulative","num":0}]}    // ]};    // filter only needed to be drawed data.    var validEchartData = {        "NCDR(A&B)":{"name":"NCDR(A&B)","num":[]},        "NCDR Cumulative": {"name":"NCDR Cumulative","num":[]},        "Monthly Target":{"name":"Monthly Target","num":[]},        "Target Cumulative": {"name":"Target Cumulative","num":[]},        "Baseline": {"name":"Baseline","num":[]}    };    var ECHAT_NAMES = ["NCDR(A&B)","NCDR Cumulative", "Monthly Target", "Target Cumulative", "Baseline"];    var data_restructure = {inside_data: [], xaxis:[]};    (data.results || []).forEach(function (d, i) {        data_restructure["xaxis"].push(d.date);        (d.stats||[]).forEach(function (dd) {            if (ECHAT_NAMES.indexOf(dd.name) != -1) {                validEchartData[dd.name]["num"].push(dd.num);            }        });    });    data_restructure.inside_data = _.values(validEchartData);    ncdr_echart_draw(data_restructure, formatTitleDate(data.interval), graph_ID);    draw_table(data, tableParams);}

Function passby object

原boject更改值成功，在Lodash的_.sortBy之后！
函数，先对输入object进行排序，然后对最小的加true标签，其他的加false标签。
我也是稀里糊涂的就实现了这个功能， 但是实在没有明白为什么。
根据打印，lodash 的sortBy之后的结果和原来的obj是完全不一样的，而我的更改是基于sortby之后的结果，为什么obj也跟着变化了？

function test(obj,key) {    console.log("obj_orig======\n%j", obj);    console.log("obj_sortby=====\n%j", _.sortBy(obj, ['age', 'user']));    console.log("obj_after_sortby=====\n%j", obj);    _.sortBy(obj, ['age', 'user']).forEach(function(d, i) { d[key] = (0===i) ? true : false;});    console.log("after_change======\n%j", obj);}var users = [    { 'user': 'Halen',   'age': 48 },    { 'user': 'barney', 'age': 36 },    { 'user': 'fred',   'age': 40 },    { 'user': 'Jack', 'age': 34 }];test(users ,"zzz");运行结果输出==========================obj_orig======[{"user":"Halen","age":48},{"user":"barney","age":36},{"user":"fred","age":40},{"user":"Jack","age":34}]obj_sortby=====[{"user":"Jack","age":34},{"user":"barney","age":36},{"user":"fred","age":40},{"user":"Halen","age":48}]obj_after_sortby=====[{"user":"Halen","age":48},{"user":"barney","age":36},{"user":"fred","age":40},{"user":"Jack","age":34}]after_change======[{"user":"Halen","age":48,"zzz":false},{"user":"barney","age":36,"zzz":false},{"user":"fred","age":40,"zzz":false},{"user":"Jack","age":34,"zzz":true}]

当然上面函数可以这样变化这里写代码片

function add_mapping_key_val(obj, key){    (obj||[]).forEach(function(d, i){ d[key] = (0 === i) ? true : false; });}var users = [    { 'user': 'Halen',   'age': 48 },    { 'user': 'barney', 'age': 36 },    { 'user': 'fred',   'age': 40 },    { 'user': 'Jack', 'age': 34 }];add_mapping_key_val(_.sortBy(users,['age', 'user']),"zzz");

Split a Long Array to smaller arrays use JS

大数组分割成多个小数组

function split_arr(arr, slice_num) { //split arr to subArr by every slice_num    var tmpArr = [];    while (arr.length > 0) {        tmpArr.push(arr.splice(0, slice_num));    }    return tmpArr;}

读取某个路径下的文件名，看是否包含需要的名字, 返回该文件的完整路径名。

// get TargetBD filefunction getTargetBD(path) {    return fs.readdirAsync(path)        .filter(function(fileName) {            return /^[Tt]arget[Bb][Dd].*\.xml$/.test(fileName);        })        .then(function(list) {            if (!list.length) {                logger.error("TargetBD not found from " + path);                return Promise.reject();            } else if (list.length !== 1) {                logger.error("Found " + list.length + " TargetBD files from " + path);                return Promise.reject();            } else {                logger.info("Found ", list[0]);                return Promise.resolve(Path.join(path, list[0]));            }        });}