66 lines
1.8 KiB
JavaScript
66 lines
1.8 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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String.prototype.format = function string_format() {
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// there are two modes of operation... unnamed indices are read in order;
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// named indices using %(name)s. The two styles cannot be mixed.
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// Unnamed indices can be passed as either a single argument to this function,
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// multiple arguments to this function, or as a single array argument
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let curindex = 0;
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let d;
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if (arguments.length > 1) {
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d = arguments;
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}
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else
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d = arguments[0];
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function r(s, key, type) {
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if (type == '%')
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return '%';
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let v;
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if (key == "") {
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if (curindex == -1)
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throw Error("Cannot mix named and positional indices in string formatting.");
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if (curindex == 0 && (!(d instanceof Object) || !(0 in d))) {
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v = d;
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}
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else if (!(curindex in d))
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throw Error("Insufficient number of items in format, requesting item %i".format(curindex));
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else {
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v = d[curindex];
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}
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++curindex;
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}
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else {
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key = key.slice(1, -1);
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if (curindex > 0)
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throw Error("Cannot mix named and positional indices in string formatting.");
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curindex = -1;
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if (!(key in d))
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throw Error("Key '%s' not present during string substitution.".format(key));
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v = d[key];
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}
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switch (type) {
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case "s":
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if (v === undefined)
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return "<undefined>";
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return v.toString();
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case "r":
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return uneval(v);
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case "i":
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return parseInt(v);
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case "f":
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return Number(v);
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default:
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throw Error("Unexpected format character '%s'.".format(type));
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}
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}
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return this.replace(/%(\([^)]+\))?(.)/g, r);
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};
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