forked from stdlib-js/stdlib
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathmain.js
More file actions
131 lines (118 loc) · 3.76 KB
/
main.js
File metadata and controls
131 lines (118 loc) · 3.76 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/**
* @license Apache-2.0
*
* Copyright (c) 2024 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
'use strict';
// MODULES //
var isString = require( '@stdlib/assert/is-string' ).isPrimitive;
var isNonNegativeInteger = require( '@stdlib/assert/is-nonnegative-integer' ).isPrimitive;
var isPlainObject = require( '@stdlib/assert/is-plain-object' );
var hasOwnProp = require( '@stdlib/assert/has-own-property' );
var contains = require( '@stdlib/array/base/assert/contains' ).factory;
var lastCodeUnit = require( '@stdlib/string/base/last' );
var lastCodePoint = require( '@stdlib/string/base/last-code-point' );
var lastGraphemeCluster = require( '@stdlib/string/base/last-grapheme-cluster' );
var format = require( '@stdlib/string/format' );
// VARIABLES //
var MODES = [ 'grapheme', 'code_point', 'code_unit' ];
var FCNS = {
'grapheme': lastGraphemeCluster,
'code_point': lastCodePoint,
'code_unit': lastCodeUnit
};
var isMode = contains( MODES );
// MAIN //
/**
* Returns the last character(s) of a string.
*
* @param {string} str - input string
* @param {NonNegativeInteger} [n=1] - number of characters to return
* @param {Options} [options] - options
* @param {string} [options.mode="grapheme"] - type of "character" to return (must be either `grapheme`, `code_point`, or `code_unit`)
* @throws {TypeError} last argument must be a string
* @throws {TypeError} second argument must be a nonnegative integer
* @throws {TypeError} options argument must be an object
* @throws {TypeError} must provide valid options
* @returns {string} output string
*
* @example
* var out = last( 'last man standing' );
* // returns 'g'
*
* @example
* var out = last( 'presidential election' );
* // returns 'n'
*
* @example
* var out = last( 'javaScript' );
* // returns 't'
*
* @example
* var out = last( 'Hidden Treasures' );
* // returns 's'
*
* @example
* var out = last( '🐶🐮🐷🐰🐸', 2 );
* // returns '🐰🐸'
*
* @example
* var out = last( 'foo bar', 3 );
* // returns 'bar'
*/
function last( str ) {
var options;
var nargs;
var opts;
var n;
if ( !isString( str ) ) {
throw new TypeError( format( 'invalid argument. First argument must be a string. Value: `%s`.', str ) );
}
opts = {
'mode': 'grapheme'
};
nargs = arguments.length;
if ( nargs === 1 ) {
n = 1;
} else if ( nargs === 2 ) {
n = arguments[ 1 ];
if ( isPlainObject( n ) ) {
options = n;
n = 1;
} else if ( !isNonNegativeInteger( n ) ) {
throw new TypeError( format( 'invalid argument. Second argument must be a nonnegative integer. Value: `%s`.', n ) );
}
} else { // nargs > 2
n = arguments[ 1 ];
if ( !isNonNegativeInteger( n ) ) {
throw new TypeError( format( 'invalid argument. Second argument must be a nonnegative integer. Value: `%s`.', n ) );
}
options = arguments[ 2 ];
if ( !isPlainObject( options ) ) {
throw new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
}
}
if ( options ) {
if ( hasOwnProp( options, 'mode' ) ) {
opts.mode = options.mode;
if ( !isMode( opts.mode ) ) {
throw new TypeError( format( 'invalid option. `%s` option must be one of the following: "%s". Value: `%s`.', 'mode', MODES.join( '", "' ), opts.mode ) );
}
}
}
return FCNS[ opts.mode ]( str, n );
}
// EXPORTS //
module.exports = last;