45 lines
1.6 KiB
JavaScript
45 lines
1.6 KiB
JavaScript
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/* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
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/*
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* This function is intended to extend the String object and provide
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* an String.format API for string formatting.
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* It has to be set up using String.prototype.format = Format.format;
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* Usage:
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* "somestring %s %d".format('hello', 5);
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* It supports %s, %d and %f, for %f it also support precisions like
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* "%.2f".format(1.526)
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*/
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function format() {
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let str = this;
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let i = 0;
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let args = arguments;
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return str.replace(/%(?:\.([0-9]+))?(.)/g, function (str, precisionGroup, genericGroup) {
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if (precisionGroup != '' && genericGroup != 'f')
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throw new Error("Precision can only be specified for 'f'");
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switch (genericGroup) {
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case '%':
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return '%';
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break;
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case 's':
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return args[i++].toString();
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break;
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case 'd':
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return parseInt(args[i++]);
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break;
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case 'f':
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if (precisionGroup == '')
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return parseFloat(args[i++]);
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else
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return parseFloat(args[i++]).toFixed(parseInt(precisionGroup));
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break;
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default:
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throw new Error('Unsupported conversion character %' + genericGroup);
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}
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});
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}
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