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feat: added depth option to flatten, defaults depth parameter to 1 if…
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… not given

the flatten method no longer flattens array to any deep length by default, you have to specify your
desired depth length
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@teclone
teclone committed Jun 16, 2019
1 parent 70927db commit 1fdb1a7
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Showing 2 changed files with 77 additions and 51 deletions.
108 changes: 60 additions & 48 deletions src/index.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ export declare interface Callback {
[propName: string]: any;
}

export declare interface CallbackCache <C extends Function = Callback, P = any> {
export declare interface CallbackCache<C extends Function = Callback, P = any> {
callback: C;
parameters?: P | P[],
scope?: object;
Expand All @@ -34,7 +34,7 @@ const _pickValue = (key: string, object: object) => {
const value = object[key];
return value;
}
catch(ex) {
catch (ex) {
return undefined;
}
};
Expand Down Expand Up @@ -113,7 +113,7 @@ export const isRegex = (arg: any): arg is RegExp => {
/**
* test if argument is a javascript object, but not an array, Regex, function or null
*/
export const isObject = <T=object>(arg: any): arg is T => {
export const isObject = <T = object>(arg: any): arg is T => {
return typeof arg === 'object' && arg !== null && !isCallable(arg) && !isArray(arg)
&& !isRegex(arg);
};
Expand Down Expand Up @@ -152,7 +152,7 @@ export const makeArray = <T>(arg: T | T[] | null | undefined, isNullable: boolea
return arg;
}

return isParameter(arg, isNullable)? [arg] : [];
return isParameter(arg, isNullable) ? [arg] : [];
};

export function makeObject<T extends object>(arg: T): T;
Expand Down Expand Up @@ -273,13 +273,13 @@ export function scopeCallback(callbackCache: CallbackCache): (...args) => any;
/**
* scope callback using the given scope and parameters
*/
export function scopeCallback<T=any>(callback: Callback, scope?: object,
export function scopeCallback<T = any>(callback: Callback, scope?: object,
parameters?: T | T[]): (...args) => any;

/**
* generates a callback function, scoping the execution with optional extra parameters
*/
export function scopeCallback<T=any>(callback: Callback | CallbackCache,
export function scopeCallback<T = any>(callback: Callback | CallbackCache,
scope: object = null, parameters: T | T[] = []) {

if (isObject<CallbackCache>(callback)) {
Expand All @@ -291,7 +291,7 @@ export function scopeCallback<T=any>(callback: Callback | CallbackCache,
try {
return callback.callback.apply(scope, [...args, ...parameters]);
}
catch(ex){
catch (ex) {
// do nothing
}
};
Expand All @@ -302,7 +302,7 @@ export function scopeCallback<T=any>(callback: Callback | CallbackCache,
try {
return callback.apply(scope, [...args, ... (parameters as T[])]);
}
catch(ex){
catch (ex) {
// do nothing
}
};
Expand All @@ -313,7 +313,7 @@ export function scopeCallback<T=any>(callback: Callback | CallbackCache,
* schedules the execution of a scoped callback to a given time
*/
export const scheduleCallback = (scopedCallback: Callback, time: number = 1000) => {
return new Promise(function(resolve) {
return new Promise(function (resolve) {
setTimeout(() => {
resolve(scopedCallback());
}, time);
Expand Down Expand Up @@ -350,7 +350,7 @@ export const generateRandomDigits = (length: number = 4): string => {
export const generateRandomText = (length: number = 4, exemptNumerals: boolean = false): string => {
const letters = alphabets + alphabets.toUpperCase();

const chars = exemptNumerals? letters : letters + digits;
const chars = exemptNumerals ? letters : letters + digits;
const result: string[] = [];

while (length--) {
Expand All @@ -376,8 +376,8 @@ export function range(from: string | number, to: string | number,
step: number = 1): number[] | string[] {

const result = [];
const letters = from.toString().toLowerCase() !== from? alphabets.toUpperCase() : alphabets;
step = step <= 0? 1 : step;
const letters = from.toString().toLowerCase() !== from ? alphabets.toUpperCase() : alphabets;
step = step <= 0 ? 1 : step;

//resolve start and end points
let start: number = null;
Expand Down Expand Up @@ -409,12 +409,13 @@ export function range(from: string | number, to: string | number,
}

if (isString(from)) {
step = step >= 1? Math.ceil(step) : 1;
for(start; start <= end; start += step)
step = step >= 1 ? Math.ceil(step) : 1;
for (start; start <= end; start += step) {
result.push(letters[start]);
}
}
else {
for(start; start <= end; start += step) {
for (start; start <= end; start += step) {
result.push(start);
}
}
Expand All @@ -426,26 +427,37 @@ export function range(from: string | number, to: string | number,
/**
* flattens arrays to any deep length
* @param arr array to flatten
* @param depth the depth value to enter
*/
export const flatten = <T>(arr: Array<T>) => {
const result: Array<T> = [];
return arr.reduce((result, current) => {
if (!isArray(current)) {
result.push(current);
return result;
}
else {
return result.concat(flatten(current));
export const flatten = <T>(arr: Array<T>, depth: number = 1) => {
if (depth < 1) {
return Array.prototype.slice.call(arr);
}
return (function flat(arr: Array<T>, depth: number) {
let result: Array<T> = [];

const len = arr.length;
let i = 0;
depth = depth - 1;
while (i < len) {
const el = arr[i++];
if (Array.isArray(el)) {
result = result.concat(depth > 0? flat(el, depth) : el);
}
else {
result.push(el);
}
}
}, result);
return result;
})(arr, depth);
};


/**
* copies the objects into the target object, without creating references, unlike Object.assign
*/
export const copy = <T extends object, O extends object>(target: T, ...objects: O[]): T & {
[P in keyof O] : O[P]
[P in keyof O]: O[P]
} => {

const cloneEach = (dest: any, value: any) => {
Expand Down Expand Up @@ -475,15 +487,15 @@ export const copy = <T extends object, O extends object>(target: T, ...objects:
}
});

return target as T & {[P in keyof O] : O[P]};
return target as T & { [P in keyof O]: O[P] };
};

/**
* converts text to camel like casing
*/
export const camelCase = (text: string, delimiter: string | RegExp = /[-_\s]/): string => {
return text.split(delimiter).map((token, index) => {
return index === 0? token : token.charAt(0).toUpperCase() + token.substring(1);
return index === 0 ? token : token.charAt(0).toUpperCase() + token.substring(1);
}).join('');
};

Expand All @@ -502,32 +514,32 @@ export const snakeCase = (text: string, delimiter: string | RegExp = /[-_\s]/):
*/
export const applyCase = (text: string, caseStyle: number,
delimiter: string | RegExp = /[-_\s]/): string => {
switch(caseStyle) {
switch (caseStyle) {

case CASE_STYLES.CAMEL_CASE:
return camelCase(text, delimiter);
case CASE_STYLES.CAMEL_CASE:
return camelCase(text, delimiter);

case CASE_STYLES.SNAKE_CASE:
return snakeCase(text, delimiter);
case CASE_STYLES.SNAKE_CASE:
return snakeCase(text, delimiter);

default:
return text;
}
default:
return text;
}
};

/**
* capitalizes the given text
* @param text text to capitalize
*/
export const capitalize = (text: string): string => {
return text.length > 0? text.charAt(0).toUpperCase() + text.substring(1).toLowerCase() : '';
return text.length > 0 ? text.charAt(0).toUpperCase() + text.substring(1).toLowerCase() : '';
}

/**
* expands the string key and turns it into an object property
*/
export const expandProperty = <T extends object>(target: T, key: string, value: any, delimiter: string = '.',
caseStyle: number = CASE_STYLES.CAMEL_CASE): T & {[propName: string]: any} => {
caseStyle: number = CASE_STYLES.CAMEL_CASE): T & { [propName: string]: any } => {

const keys = key.split(delimiter);
const lastKey = applyCase(keys.pop(), caseStyle);
Expand All @@ -547,7 +559,7 @@ export const expandProperty = <T extends object>(target: T, key: string, value:
* pads the given target text or number with the pad with value until the target length meets
* the given length
*/
export const padLeft = (target: string | number, length=4, padWith: string | number = 0): string => {
export const padLeft = (target: string | number, length = 4, padWith: string | number = 0): string => {
target = target.toString();
padWith = padWith.toString();

Expand All @@ -563,7 +575,7 @@ export const padLeft = (target: string | number, length=4, padWith: string | num
* pads the given target text or number with the pad with value until the target length meets
* the given length
*/
export const padRight = (target: string | number, length=4, padWith: string | number = 0): string => {
export const padRight = (target: string | number, length = 4, padWith: string | number = 0): string => {
target = target.toString();
padWith = padWith.toString();

Expand All @@ -582,7 +594,7 @@ export const padRight = (target: string | number, length=4, padWith: string | nu
* @param multiValueIdentifier an identifier to be prepended to multivalue query names for
* identification.
*/
export const encodeQuery = (name: string, value: string | number | (string|number)[],
export const encodeQuery = (name: string, value: string | number | (string | number)[],
multiValueIdentifier: string = '[]'): string => {
name = encodeURIComponent(name);
if (isArray(value)) {
Expand All @@ -601,7 +613,7 @@ export const encodeQuery = (name: string, value: string | number | (string|numbe
* @param multiValueIdentifier an identifier to be prepended to multivalue query names for
* identification.
*/
export const encodeQueries = (query: {[name: string]: string | number | (string | number)[]},
export const encodeQueries = (query: { [name: string]: string | number | (string | number)[] },
multiValueIdentifier: string = '[]'): string => {
return Object.keys(query).map(name => {
return encodeQuery(name, query[name], multiValueIdentifier);
Expand All @@ -622,18 +634,18 @@ export const expandToNumeric = (size: number | string): number => {
let numeric = Number.parseFloat(RegExp.$1);
const unit = RegExp.$2.toLowerCase();

switch(unit) {
switch (unit) {
case 'k':
return numeric * 1000;
return numeric * 1000;
case 'm':
case 'mb':
return numeric * 1000000;
return numeric * 1000000;
case 'g':
case 'gb':
return numeric * 1000000000;
return numeric * 1000000000;
case 't':
case 'tb':
return numeric * 1000000000000;
return numeric * 1000000000000;
}
}
else {
Expand All @@ -647,7 +659,7 @@ const convertToUnit = (units: string[], value: number, maximumFractionDigits: nu
const length = snapPoints.length;
let i = -1;

const formatter = new Intl.NumberFormat(undefined, {maximumFractionDigits});
const formatter = new Intl.NumberFormat(undefined, { maximumFractionDigits });
while (++i < length) {
const snapPoint = snapPoints[i];
const unit = units[i];
Expand Down
20 changes: 17 additions & 3 deletions tests/index.spec.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -468,10 +468,24 @@ describe('Utils', function() {
});
});

describe('.flatten<T>(arr: Array<T>)', function() {
it(`should flatten the given array to any deep length`, function() {
describe('.flatten<T>(arr: Array<T>, depth: number = 1)', function() {
it(`should flatten the given array up to the given length`, function() {
const testData = [1, 2, 3, 4, [5, 6, [7, 8, 9, [10]]]];
expect(Utils.flatten(testData)).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
expect(Utils.flatten(testData, 2)).toEqual([
1, 2, 3, 4, 5, 6, 7, 8, 9, [10]
]);
});

it(`should default the depth parameter to 1 if not given`, function() {
const testData = [1, 2, 3, 4, [5, 6, [7, 8, 9, [10]]]];
expect(Utils.flatten(testData)).toEqual([
1, 2, 3, 4, 5, 6, [7, 8, 9, [10]]
]);
});

it(`should do nothing but return the array if the depth parameter is less than 1`, function() {
const testData = [1, 2, 3, 4, [5, 6, [7, 8, 9, [10]]]];
expect(Utils.flatten(testData, -1)).toEqual(testData);
});
});

Expand Down

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