54 lines
1.4 KiB
JavaScript
54 lines
1.4 KiB
JavaScript
var util = require("../../util");
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var t = require("../../types");
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exports.Function = function (node, parent, scope, context, file) {
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if (!node.rest) return;
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var rest = node.rest;
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node.rest = null;
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t.ensureBlock(node);
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var argsId = t.identifier("arguments");
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// otherwise `arguments` will be remapped in arrow functions
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argsId._ignoreAliasFunctions = true;
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var start = t.literal(node.params.length);
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var key = file.generateUidIdentifier("key");
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var len = file.generateUidIdentifier("len");
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var arrKey = key;
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var arrLen = len;
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if (node.params.length) {
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// this method has additional params, so we need to subtract
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// the index of the current argument position from the
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// position in the array that we want to populate
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arrKey = t.binaryExpression("-", key, start);
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// we need to work out the size of the array that we're
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// going to store all the rest parameters
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//
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// we need to add a check to avoid constructing the array
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// with <0 if there are less arguments than params as it'll
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// cause an error
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arrLen = t.conditionalExpression(
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t.binaryExpression(">", len, start),
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t.binaryExpression("-", len, start),
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t.literal(0)
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);
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}
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node.body.body.unshift(
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util.template("rest", {
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ARGUMENTS: argsId,
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ARRAY_KEY: arrKey,
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ARRAY_LEN: arrLen,
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START: start,
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ARRAY: rest,
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KEY: key,
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LEN: len,
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})
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);
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};
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